Does the Vegan Diet Help You Lose Weight?


One of the most common questions I get is whether or not the vegan diet helps with weight loss. Yes, vegans are characteristically thin, but is that all correlation or is there some causation in there somewhere?

I remember when I first asked myself this question. The answer wasn’t immediately obvious, however, after much digging, I was able to uncover many ways in which plant-based eating affects body composition.

Does the vegan diet help you lose weight? Yes. According to Ming-Chin Yeh, et al. researchers and authors of Vegetarian and Plant-Based Diets in Health and Disease, “With few exceptions, clinical trials indicate that plant-based diets translate into greater weight loss than omnivorous control diets.”1

There are many ways in which a well-planned whole food vegan diet can help aid weight loss. And if you want to know how then keep reading.

The Vegan Diet and Body Composition

I know what you’re probably thinking: “yes I know that the vegan diet has been shown to be a near panacea, helping to prevent and even reverse a range of health problems, but obesity? I thought that weight management was simply a matter of calories in vs. calories out. Can the vegan diet really help with weight loss?” Absolutely! How do we know?

The Proof Is in the Dairy-Free Pudding

A 2006 literature review of weight status of vegetarians and nonvegetarians found that 38 of 40 studies reported lower body mass index (BMI) and body weight among vegetarians.2

In 2009, the Academy of Nutrition and Dietetics (AND)—then the American Dietetic Association or ADA—released a position paper recognizing the role of vegetarian and vegan diets in the prevention of chronic diseases, including obesity.3

Where did they get such an idea?

The supposed role of plant-based diets in weight management was initially based on several population studies that found an association between plant-based eating patterns and lower BMI.

A couple of years later in 2011, the AND followed up with an editorial supporting the role of vegetarian and vegan diets in achieving weight loss and long-term weight maintenance.4

What we’ll do first is explore both population studies and clinical trials that evaluate the efficacy of whole food vegetarian diets in achieving and maintaining a healthy BMI.

In doing so, we’ll cover some of the mechanisms by which plant-based diets are thought to aid in achieving a healthy body composition.

As I harp on quite a bit, vegetarian diets are not created equal, and given the importance of diet quality in the area of body weight regulation, I’ll be using the term plant-based synonymously with vegetarian and vegan diets.

Evidence from Population Studies

This type of study can provide tons of insight into potential relationships between specific diets and BMI/weight management.

USDA Continuing Survey of Food Intake

The USDA’s 1994–1996 Continuing Survey of Food Intake (CSFI) looked at over 10,000 individuals, comparing vegetarian and non-vegetarian diets. They found that those following plant-based diets had lower BMIs, lower energy intake, and lower intakes of total and saturated fat.5

NHANES

Another study with a long acronym for its name is the National Health and Nutrition Examination Survey (NHANES). Data from 1999 to 2004 NHANES also indicated a lower energy intake among survey participants who reported no meat consumption.6

Adventist Health Study 2

And, of course, no analyses of vegetarian population studies would be complete without looking at data from Adventist Health Studies. In fact, the Adventist Health Study 2 was probably the most expansive population analysis looking at plant-based diets. This study followed 97,000 SDA church members, age 30 and older, in the US and Canada between 2002 and 2006, and actually looked at vegans specifically.

The study found that:7

  1. Vegans had the lowest BMI: 23.6 kg/m2
  2. Then ovolactovegetarians: 25.7
  3. Pescetarians: 26.3
  4. Semivegetarians: 27.3
  5. Last and in this case, least: nonvegetarians with a BMI of 28.8
EPIC-Oxford Study

These findings (vegans having the lowest BMI followed by vegetarians and then nonvegetarians) reflect the results of the EPIC-Oxford cohort study wherein 57,498 participants completed food frequency questionnaires (FFQs) between 1993 and 1999.

BMI analysis from this study revealed comparatively large differences between diet groups with the highest BMI prize going to meat eaters and lowest to vegans, with vegetarian and pescatarians falling somewhere in between.8

In this study, obesity rates were significantly lower among vegan populations (1.9% and 1.8% for men and women, respectively). Contrast that with the BMI among meat eaters: obesity rates of 5%  and 5.7% for men and women, respectively).

The study authors concluded that protein and fiber intakes were the strongest determinants of BMI.

Another study was conducted a bit later on which looked at annual rates of weight gain among EPIC-Oxford cohort participants. In this analysis, the authors found that those who switched to a diet with fewer animal products to display the lowest weight gain.9

So, as you can see, while there are lots of vegetarian studies, there aren’t a ton of studies looking at vegans specifically.

But the ones that exist show strict vegans to have the lowest body fat, while vegetarians are either similar or slightly lower in body fat compared to nonvegetarians.

In the EPIC-Oxford Study, researchers found that vegetarians have a BMI around one point (1 kg/m2) lower than nonvegetarians, which translates into much lower rates of obesity.

Vegans (counted among the vegetarian group) were shown to have significantly lower BMI scores than carnivores—at all ages vegans had a lower mean BMI than meat eaters (by about 1-2 kg m2).10

When citing such studies, one common objection is “Hey, bro don’t you know that correlation doesn’t equal causation!” Ah, the age-old correlation-causation argument… every bro’s favorite fallacy.

But the point is taken, and it’s a valid one. Just because vegans have on average a lower BMI doesn’t mean that their eating pattern is responsible for the lower level of body fat. After all, those who are vegan may be, on average, healthier in general—more interested in healthy, more likely to exercise, etc.

However, in the above study, the differences in physical activity did not seem to contribute to the lower body fat levels observed when you take into account that most studies comparing vegetarian and nonvegetarian populations show very little differences in physical activity between the two populations.11-15

Anyway, that’s where clinical trials come in.

Clinical Trials

This is important. You can learn a lot from population studies, but clinical trials are where it’s at when it comes to determining causality.

For example, in the last bit, I mentioned EPIC-Oxford cohort participants were studied for their rate of weight gain, and that those switching to a diet with fewer animal products had the lowest rate of weight gain.

Well, one could argue that those who decided to switch to more of a plant-based diet are likely to have been more health conscious than other participants, which might confound the results.

Confounding variables like this are what make it so difficult to draw diet-BMI conclusions from population studies.

By looking at clinical trials in which lifestyle variables can be more closely controlled, we can really get to the bottom of things.

Vegetarian Meta-Analysis 1

One meta-analysis looked at 10 prospective cohort studies and 86 cross-sectional studies and reported markedly reduced BMI scores in vegetarians and vegans, compared to omnivores.16

Vegetarian Meta-Analysis 2

Another meta-analysis looked at 12 randomized trials (RCTs) and found there were significant weight loss benefits to be had from consuming vegetarian diets. Six of the RTCs incorporated energy restriction (e.g. 500 kcal/day) and found the effect to be especially pronounced.17

Literature Review by Berkow, S., Barnard, N.

Berko S. and Barnard N. found that in RTCs specifically (the best form of research), participants following vegetarian and vegan diets lose anywhere from an extra 2.5 to 7.2 kg compared to controls.2

Huang et al. Say Vegan Diets Rule When It Comes to Weight Loss

But in a much more articulate manner. Upon looking at multiple clinical studies, Huang et al. stated that the weight loss benefits from plant-based diets seem to be greatest for those on a vegan diet.17

Large Vegan Intervention Study

An 18-week dietary intervention study (the gold standard of gold standard studies) found the 94 participants assigned to a low-fat vegan diet to lose markedly more weight (~6 lbs.) than the 117 control subjects (a measly 0.13 lb.). And this was in the absence of prescribed caloric restriction and exercise.18

A Large Vegan Weight Loss Study

Yet another large study looking at vegan diets and weight loss. One study by Turner-McGrievy, et al. looked at 50 overweight adults and found those assigned to a vegan diet to lose significantly more weight than those assigned to semivegetarian, pescetarian and omnivorous diets at the six-month mark.19

A Long-Term Vegan Weight Loss Study

One long intervention study found the vegan diet to result in greater weight loss among a group of 59 overweight and obese women at the 14-week mark, compared to a moderately low-fat diet. The results seemed to stick too, as the achieved weight loss had been maintained at both the 1- and 2-year follow-ups.20

Vegan Diet Meta-Analysis

Another meta-analysis looked at 15 clinical trials and found that a prescribed vegan diet was associated with a mean reduction in weight of 3.4 to 4.6 kg. The ovolactovegetarian performed equally well in this study.21

As with the study by Mishra, et al. these results were obtained without any prescription for exercise or caloric restriction.

A few caveats

Not every clinical trial of this kind reported better weight loss results with plant-based diets. Especially, when calories are controlled for. That’s to be expected, though, as the weight loss is a matter of calories in vs. calories out.

For example, one study (~180 participants) had subjects assigned to one of two calorie-restricted diets: either a vegetarian diet or a standard diet. At the six-month mark, comparable weight loss was observed in both groups. The authors noted a lack of compliance in the vegetarian group. But, again, we need not look for any explanations.22

Again, a calorie is a calorie. What makes one diet better than another is the degree to which it helps you adhere to a calorie deficit over the long-term. So, if plant-based diets are better for weight loss—which it appears that they are—it’s only insofar as they are conducive to maintaining a caloric deficit.

Another thing to keep in mind is that few clinical trials are long enough to draw any conclusions about whether a given diet yields lasting results. To determine if eating patterns yield long-term results, studies need to be at least 2 years long.23,17,21

We looked at one above, but there really aren’t that many 2+ year studies at this point. Several studies indicate that vegan groups are every bit as likely to regain lost weight—which could be due to the fact that participants in the study don’t follow vegetarian and vegan diets long-term.

This is a good time to point out how important it is that you view eating patterns as a lifestyle, and not a diet.

Two studies finding weight loss benefits as a result of following a vegan diet found that while substantial weight loss was achieved initially, the benefits disappeared after about 6 months to 1 year later.24,17

In 2008, Burke et al. found both the omnivore and ovolactovegetarian groups to regain lost weight a few months after the conclusion of a 1-year intervention.25

Summing Up the Studies

From looking at the above studies (especially EPIC-Oxford, NHANES, and AHS-2) we get a pretty clear picture of the relationship between BMI and diet type with the lowest BMI among vegans and highest among meat eaters, with those following less strict forms of vegetarianism falling somewhere in between.7,8,6

Some clinical studies even showed plant-based diets to be effective for weight loss, even in the absence of calorie restriction.17,23,21

The Importance of Dietary Adherence

Yes, we went over this above. But, it’s so important that it merits closing the article with. No matter what eating pattern you choose to adopt, you will never see the results you’re looking (for weight or any other measure of health) if you treat it as a temporary “diet” instead of a lifestyle. 

One thing weight loss researchers tend to agree on is that weight regain tends to be the norm. At this point, there is insufficient evidence to suggest that weight loss via plant-based diets—or any other “diet”—contribute to long-term weight control and maintenance.

One survey of dietary counseling studies found a modest treatment effect (modest as in 2 BMI units of weight loss) throughout the first year of counseling, but half of this modest improvement was lost when weight was regained after 3 years.23

About 20% of overweight adults maintain their weight loss past 1 year is considered par for the course.26

At the beginning of the article, we looked at population studies. And while such studies can’t confirm causality, they’re great when it comes to showing us what the potential benefits could be of adopting certain lifestyles.

 Populations like the SDA groups are followed over decades. They don’t just start a diet in hopes of sticking to it for a few months, or for the duration of a study.

In many cases, they’re raised to eat a certain way, and as a result see less incidence of obesity, overweight, and a host of other diseases and conditions.


Well, How Exactly Is the Vegan Diet Superior for Fat Loss?

So, we’ve established that plant-based eaters tend to be leaner and that switching to a vegan diet is likely to result in weight loss.

Now, we’re going to get to the “how.” What is it about plant-based diets that could account for this effect? There are many potential reasons for the beneficial effect of the vegan diet on body fat levels.

Explanations range from the very practical—such as an increase in food volume when you switch to a plant-based diet, to more speculative explanations pertaining to the cutting-edge research on the microbiome.

In the Oxford study above, researchers speculated that the lower BMI of vegetarians and vegans was related at least in part, to higher intakes of fiber and lower intakes of animal fat.

The following are the main explanations that researchers have converged on:

  1. Energy density
  2. Carbohydrate and fiber content
  3. Fat content
  4. Gut microbiota: plant-based diets and reduced inflammation
  5. Increased metabolism

So, let’s get down to it, starting with energy density.

Low Energy Density

The consumption of energy sparse foods (foods with high water content, and few calories) is absolutely fundamental to any effective weight loss plan.27,28

What Is Energy Density?

Foods that are characteristically high in water and fiber, but low in calories include fruits, vegetables, and to a lesser degree cooked grains. Diets rich in fruits and vegetables, but low in fat are associated with weight loss and better weight maintenance.29,30

Fat isn’t inherently unhealthy, and as you’ll see this macronutrient does have a place in an effective weight loss eating plan. But high bulk/low-fat diets are associated with weight loss because fat is energy dense—having about twice the energy of protein and carbs.

Low energy density in itself may be more important for weight maintenance than weight loss per se. This is because there’s very little evidence suggesting that the simple addition of low energy density plant foods results in weight loss without a conscious reduction in total calorie intake. At least, in the long term.

Simply adding fruits and veggies without an accompanying effort to reduce calories would likely only result in short term weight loss. A spontaneous reduction in calories only lasts so long, and when you break even in calorie consumption, you’ll hit a weight loss plateau.

But, the addition of fruits and vegetables, absent any conscious calorie counting, can go a long way in helping you maintain a healthy weight—as well as help you maintain any weight loss you’ve achieved in previous bouts of dieting.

For example, one study of normal weight adults, overweight adults, and a group of adults maintaining their weight loss found that those successfully maintaining their weight loss consumed a diet markedly lower in energy density—specifically, they reported higher intake of vegetables and whole grains and lower intakes of fat.31

Bottom line: it’s the overall lack of energy density (for which fruits and veggies play a role) that contributes to the ability of plant-based diets to help us manage our weight. While calories in vs. calories out will always be the determining factor in whether or not we see the scale move, it’s the low energy density of plant-based diets that make them conducive to managing energy balance.

Fiber and Complex Carbohydrates

Plant-based diets are typically higher in fiber and complex carbs than other diets.32,33

How is this beneficial? Complex carbs, especially fiber, are satiating (filling) because they take a long time to digest. When your stomach has food in it, that food stretches certain receptors sending a signal to our brain that it’s full and to stop making us feel so hungry.

Because fiber and complex carbs take so long to transit the GI tract, the satiety signal tends to last much longer.

Also, many types of fiber are known to be fermentable by our gut bugs, which produce various compounds (short-chain fatty acids) that suppress appetite and perform a number of beneficial functions. Basically, there are numerous gut hormones that affect the way in which the brain regulates our appetite.

However, research shows that not all of these neurohormones are endogenous (a fancy way of saying made by our body). Many potential appetite-regulating hormones are made by the bacteria in our microbiome.

The gut microbiome has a massive influence on satiety (the sense of feeling full), and mounting evidence suggests that a certain type of fiber (technically a starch known as resistant starch) can influence appetite through its effects on gene expression.  Vegans consume upwards of four times the amount of dietary fiber compared to omnivores. After all, fiber is found only in plant foods.

Low Fat Content

It’s long been known that nutrient-dense, low-fat, plant-based diets have been associated with a wide range of favorable health outcomes, including better weight control.34

When I first encountered the literature in this area, I was a bit surprised. Fat is known to increase satiety, because—like complex carbs—it sits in the GI tract for longer than other food components.

But alas, many trials have found significant weight loss to occur among participants following a low-fat vegan diet.33,35

As an example, one 7-day study by Mcdougall, J. et al., examined the results of over 1500 participants who underwent a residential dietary intervention protocol, and found that the subjects following an ad lib low-fat (10% or less kcal from fat) vegan diet lost an average of 3 lb. in 7 days.35

There was another study in which postmenopausal women were assigned to an ad lib low-fat vegan diet (also ≤10% from fat). Participants in this study lost ~12 lb. over the course of 14 weeks compared to the control group (~8 lb.) who followed the dietary guidelines laid out by the National Cholesterol Education Program (NCEP).36

They’re both good diets, so what gives? Why the difference? Well, while both groups reported about the same reductions in energy intake, the control group decreased carbohydrate intake, whereas the vegan group increased their carbohydrate and fiber intake and in doing so pushed fat out of the diet.

Not only did the vegan group lose more weight in the short-term, but they also lost significantly more weight than the control group at both the 1- and 2- year follow-ups.20

How is this possible? After all, we know that calories in vs. calories out is the bottom line when it comes to changes in body weight. Well, the authors think that the vegan group was actually eating a greater volume of food (due to increased carb intake/decreased fat intake), but overall fewer calories—despite the two groups reporting the same reductions in energy intake.

You see, fiber doesn’t really count. Our large intestine can derive some energy from fiber and resistant starch, but fiber goes largely undigested. Eating fiber is almost like cheating! High fiber foods stretch the stomach, sending the satiety signals, but yields much energy.

Additionally, fiber may also result in reduced absorption of dietary fat.37

One study of type 2 diabetics lends credibility to this idea. The study by Kahleova, H., et al. found energy-restricted, high-carb plant-based diets to result in greater fat loss, especially from visceral fat stores.38

Lower Intake of Animal Fats

Not only does the low-fat nature of the vegan diet help aid in weight loss, but the type of fat it excludes also plays a role in helping us achieve and maintain a healthy weight.

Animal fat is largely saturated fat, which is more easily stored and less readily mobilized for burning. Overall, vegetarians tend to eat far less saturated fat than omnivores, and vegans far less than other plant-based eaters (Lacto-ovo vegetarians, etc.).

While it’s widely known that excess saturated fat in the diet raises one’s risk of heart disease, fewer people are aware of the link between excessive saturated fat and obesity. Generally speaking*, vegans consume the least amount of saturated fat compared to all other groups and thus benefit the most in this regard.

Because cholesterol is only found in animal foods, and vegans abstain from all food of animal origin, they consume no dietary cholesterol, and by extension very little saturated fat.

*The main exception would be vegans who use large amounts of tropical oils such as palm kernel and coconut oils.

Revving Up Your Metabolism!

Another interesting possible explanation is that of the hormonal environment produced by vegetarian diets. The higher carbohydrate, lower fat intake of vegetarian diets is known to increase plasma levels of norepinephrine, which is conducive to fat loss (due to its fat mobilizing and appetite suppressing properties), which may lead to vegetarians and vegans having a higher metabolic rate than carnivores.

In one study examining resting metabolic rate (RMR) in vegetarians, vegans and Lacto-ovo vegetarians in their mid-twenties were noted to have an RMR 11% higher than that of nonvegetarians.39

That is quite significant. Keep in mind many pharmaceutical drugs designed for weight loss achieve much less of a calorie burn. For a person who would otherwise burn 2,000 calories per day, that’s an additional 220 calories burned daily, which comes to about half a pound of fat lost per week.

Healthy Gut Microbiota

The gut microbiome talk is all the rage these days (did I just say all the rage?). I tend to be skeptical of such trends—health trends that seem to arise quickly and dominate the headlines. But, it seems to be much more than just another health fad.

The degree to which diet is linked with the gut microbiome is just now starting to be uncovered, and yes, there’s very little we know at this point. But, what is currently known has many implications for obesity.

Namely, obesity is characterized by the presence of an altered gut profile, where bacteria are responsible for many processes detrimental to weight control. For example:40,41

  • Providing an environment conducive to lowgrade, chronic inflammation which can lead to hyperinsulinemia, glucose intolerance, metabolic syndrome, and even type 2 diabetes.
  • Increasing the body’s ability to extract energy from food.

How does this happen?

It seems the microbiota of overweight and obese subjects is often characterized by:42-44

  • Decreased prevalence of Bacteroidetes—a class/phylum of bacteria present in human guts and on human skin.
  • The increased presence of unhealthy bacteria—Firmicutes and Actinobacteria.
  • Reduced bacterial diversity—not good. We need different bacteria for different duties.
  • An increased amount of potentially inflammatory “Proteobacteria”—a major phylum of gram-negative bacteria.
What Kind of Gut Bug Profile Do Vegans and Vegetarians Have?

Gut microbiomes have their own ecosystems. Once scientists figured this out, they decided to classify living beings based on their “enterotype”—the specific ecosystem that characterized their microbiome.

We, humans, have three enterotypes—we all have one of three ecosystems. And the specific enterotype that you have, isn’t dictated by your age, gender, etc. but rather your long-term eating habits.45-47

Type 1 would be characterized by a lot of Bacteroides-type bacteria, type 2 have more Prevotella, and type 3 tend to have a lot of Ruminococcus.45,48,49

We needn’t go into too much detail here, but just know that plant-based diets tend to be linked to enterotypes that have a greater abundance of Bacteroidetes, whereas the Standard American Diet (SAD) is associated with higher levels of Firmicutes and Actinobacteria.50,51

And if you guessed the former to be healthier, you’re right.

In one study, Matijašić et al. (2014) compared the bacterial DNA profiles (yes, taken from feces) of 29 omnivores, 11 lactovegetarians, and 20 vegans. Subjects were similar in age, gender, body weight, and height.52

After analyzing the stool samples for their bacterial profile, they found diet to be highly associated with bacterial composition. Specifically, the found the plant-based groups to have a much higher ratio of Bacteroides-Prevotella compared to the omnivore group.

Another study by Zimmer et al. looked for differences in bacterial composition between the various plant-based groups. They wanted to know if the microbiota profile of vegans tended to differ from vegetarians.53

The authors found the stool pH and gut microbiota of the vegetarian group to unsurprisingly fall somewhere between the vegan group and the omnivore control group.54

Some researchers also wanted to know if the higher fiber content of vegan diets may play a role in helping regulate systemic inflammation. If so, it could help account for the low prevalence of obesity seen in the vegan community.41,51

Researchers found the microbiota of obese participants to be associated with higher levels of inflammatory markers—plasma C-reactive protein (CRP) and fecal calprotectin.44

It’s long been known that dietary intake influences inflammation for better or worse. It’s also known that vegetarians demonstrate lower levels of CRP than omnivores.

One six month weight loss intervention compared a number of dietary groups and found a lower Dietary Inflammatory Index among vegans and vegetarians compared to omnivores at the two-month mark.55,56

One study looked at six obese subjects with hypertension and/or diabetes, who followed a vegan diet for 1 month.

By the end of the study, the group was found to have reduced body weight and improved blood glucose levels. As the participants progressed throughout the month, they were found to have a decrease in the concentrations of various inflammation markers. The accompanying reduction in inflammation was contributed to improved lipid metabolism and glucose tolerance.

How? It seems that 1 month on the vegan diet induced an altered gut microbiota by increasing the ratio of Bacteroidetes to Firmicutes.56

Again, it seems the increased dietary fiber upon switching to a vegan diet likely contributed to reductions in both obesity and inflammatory markers by way of gut microbiota alterations.

Don’t You Need Meat to Stay Full?

I’ve been waiting a long time to dismantle this meat monger myth (and a long time to say that). One myth that the low-carb keto crowd likes to spread is that you need meat to stay full and satiated. They’re right in that meat, due to its chemical (protein and fat) and physical (chewy texture) properties, is a very satiating food.

But, you don’t need it. There are plenty of protein-laden, tough-textured foods in the plant kingdom that are known to provide every bit as much satiety.

And that’s not just my opinion. Many clinical trials testing plant-based diets for weight loss have managed to manipulate various macronutrients to try and determine which food components are important when it comes to achieving weight loss results.

They pretty much all converge on the opinion that it’s far from obvious that, provided calorie restriction, the type of protein (animal or plant) consumed over the course of a diet plays a key role in the resulting weight loss.

One study compared diets that varied in protein quantity and quality found that animal proteins (meat specifically) do not differ from protein found in soy and other legumes in their effects on appetite, energy expenditure, and what’s known as thermic effect of feeding (TEF – % of calories that gets burned in the digestion of the nutrient).57

In the study Li, et al., the overweight/obese adults lost weight regardless of the source of dietary protein. The authors concluded that it was energy restriction, not protein characteristics, that had the final say on weight loss.

Another study compared two high-protein weight loss diets, one with soy protein and the other with meat. In this study, researchers found that of the 20 obese male participants, no significant differences were noted in weight loss or body fat status between the two groups by the end of two weeks. Further, there were no differences in the participants’ subjective hunger/satiety ratings.58

Wrapping It Up

Plant-based diets have many advantages over the standard Western diet, not the least of which is in the area of helping one achieve and maintain a healthy body weight. Many people are aware that plant-based diets offer protection against cancer, heart disease, diabetes, and hypertension, but few people are aware of the benefits conferred by this eating pattern on body fat status.

Numerous studies reveal that vegetarians, and especially vegans, tend to have less body fat than omnivores. Further, the above information suggests that vegans not only enjoy health advantages over omnivores but in some cases, over Lacto-ovo vegetarians.  

There are a number of potential reasons for the beneficial effects of the plant-based diet in this area, and in this article, I tried to outline the various mechanisms that are implicated—namely those related to the lower energy density, higher fiber and lower fat content of plant-based diets.

Keep in mind that the above mechanisms—from the practical to the speculative—are limited to whole-food, plant-based diets. Vegan and vegetarian diets are not a monolith, and the quality of the foods characterizing the diets of individual vegetarians can range every bit as much as the reasons they cite for adopting a vegan or vegetarian diet.

Vegan diets do offer many benefits which on balance help one achieve and maintain a healthy body fat level, but this is only true given proper implementation.

References

  1. Vegetarian and Plant-based Diets in Health and Disease Prevention (Page 335). François Mariotti – Elsevier Academic Press – 2017
  2. Berkow, S., Barnard, N., 2006. Vegetarian diets and weight status. Nutr. Rev. 64, 175–188.
  3. Craig, W.J., Mangels, A.R., 2009. Position paper of the American Dietetic Association: vegetarian diets. J. Am. Diet. Assoc. 109, 1266–1282.
  4. Thedford, K., Raj, S., 2011. A vegetarian diet for weight managment. J. Am. Diet. Assoc. 111, 816–818.
  5. Kennedy, E., Bowman, S., Spence, J., Freedman, M., King, J., 2001. Popular diets: correlation to health, nutrition, and obesity. J. Am. Diet. Assoc. 101, 411–420.
  6. Farmer, B., 2014. Nutritional adequacy of plant-based diets for weight management: observations from the NHANES. Am. J. Clin. Nutr. 100, 365s–368s.
  7. Tonstad, S., Butler, T., Yan, R., Fraser, G.E., 2009. Type of vegetarian diet, body weight, and prevalence of type 2 diabetes. Diabetes Care 32, 791–796.
  8. Spencer, E., Appleby, P., Davey, G., Key, T., 2003. Diets and body mass index in 38,000 EPIC-Oxford meateaters, fish-eaters, vegetarians and vegans. Int. J. Obes. 27, 728–734.
  9. Rosell, M., Appleby, P., Spencer, E., Key, T., 2006. Weight gain over 5 years in 21,966 meat-eating, fish-eating, vegetarian, and vegan men and women in EPIC-Oxford. Int. J. Obes. 30, 1389–1396.
  10. Spencer EA, Appleby PN, Davey GK, Key TJ. Diet and body mass index in 38000 EPIC-Oxford meat-eaters, fish eaters, vegetarians and vegans. Int J Obes Relat Metab Disord. 2003;27(6):728-734
  11. Slattery ML, Jacobs DR, Jr., Hilner JE, et al. Meat consumption and its associations with other diet and health factors in young adults.
  12. Rouse IL, Beilin LJ, Armstrong BK, Vandongen R. Blood-pressure-lowering effect of a vegetarian diet: controlled trial in normotensive subjects. Lancet. 1983;1(8314-5):5-10
  13. McKenzie J. Profile on vegans. Plant Foods Hum Nutr. 1971;2:79-88
  14. Armstrong B, van Merwyk AJ, Coates H. Blood pressure in Seventh-day Adventist vegetarians. Am J Epidemiol. 1977;105(5):444-449
  15. Janelle KC, Barr SI. Nutrient intakes and eating behavior scores of vegetarian and nonvegetarian women. J Am Diet Assoc. 1995;95(2):180-186, 189; quiz 7-8
  16. Dinu, M., Abbate, R., Gensini, G., Casini, A., Sofi, F., 2016. Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studies. Crit. Rev. Food Sci. Nutr. (Online).
  17. Huang, R.-Y., Huang, C.-C., Hu, F.B., Chavarro, J.E., 2015. Vegetarian diets and weight reduction: a metaanalysis of randomized controlled trials. J. Gen. Intern. Med. 31, 109–116.
  18. Mishra, S., Xu, J., Agarwal, U., Gonzales, J., Levin, S., Barnard, N., 2013. A multicenter randomized control trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study. Eur. J. Clin. Nutr. 67, 718–724.
  19. Turner-McGrievy, G.M., Davidson, C.R., Wingard, E.E., Wilcox, S., Frongillo, E.A., 2015b. Comparative effectiveness of plant-based diets for weight loss: a randomized controlled trial of five different diets. Nutrition 31, 350–358.
  20. Turner-Mcgrievy, G., Barnard, N.D., Scialli, A.R., 2007. A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet. Obesity 15, 2276–2281.
  21. Barnard, N.D., Levin, S.M., Yokoyama, Y., 2015. A systematic review and meta-analysis of changes in body weight in clinical trials of vegetarian diets. J. Acad. Nutr. Diet. 115 (6).
  22. Burke, L., Styn, M., Steenkiste, A., Music, E., Warziski, M., Choo, J., 2006. A randomized clinical trial testing treatment preference and two dietary options in behavioral weight management: preliminary results of the impact of diet at 6 months – PREFER study. Obesity 14, 2007–2017.
  23. Dansinger, M., Tatsioni, A., Wong, J., Chung, M., Balk, E., 2007. Meta-analysis: the effect of dietary counseling for weight loss. Ann. Intern. Med. 147, 41–50.
  24. Turner-Mcgrievy, G., Davidson, C.R., Wingard, E.E., Billings, D.L., 2014. Low glycemic index vegan or lowcalorie weight loss diets for women with polycystic ovary syndrome: a randomized controlled feasibility study. Nutr. Res. 34, 552–558.
  25. Burke, L., Warzoski, M., Styn, M., Music, E., Hudson, A., Sereika, S., 2008. A randomized clinical trial of a standard versus vegetarian diet for weight loss: the impact of treatment preference. Int. J. Obes. 32, 166–176.
  26. Wing, R., Phelan, S., 2005. Long-term weight loss maintenance. Am. J. Clin. Nutr. 82 (Suppl.).
  27. Ornish, D., Scherwitz, L., Billings, J., Gould, L., Al, E., 1998. Intensive lifestyle changes for reversal of coronary heart disease. JAMA 280, 2001–2007.
  28. Rolls, B., Drewinowski, A., Ledikwe, J., 2005. Changing the energy density of the diet as a strategy for weight management. J. Am. Diet. Assoc. 105, S98–S103.
  29. Rolls, B., Ello-Martin, J., Tohill, B., 2004. What can intervention studies tell us about the relationship between fruit and vegetable consumption and weight management? Nutr. Rev. 62, 1–17.
  30. Rolls, B., 2009. The relationship between dietary energy density and energy intake. Physiol. Behav. 97, 609–615.
  31. Raynor, H., Van Walleghen, E., Bachman, J., Looney, S., Phelan, S., Wing, R., 2011. Dietary energy density and successful weight loss maintenance. Eat. Behav. 12, 119–125.
  32. Turner-Mc-Grievy, G.M., Davidson, C.R., Wingard, E.E., Wilcox, S., Frongillo, E.A., 2015b. Comparative effectiveness of plant-based diets for weight loss: a randomized controlled trial of five different diets. Nutrition 31, 350–358.
  33. Barnard, N.D., Scialli, A.R., Turner-Mc-Grievy, G., Lanou, A.J., Glass, J., 2005. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am. J. Med. 118, 991–997.
  34. Katz, D.L., Meller, S., 2014. Can we say what diet is best for health? Annu. Rev. Public Health 35, 83–103.
  35. Mcdougall, J., Thomas, L.E., Mcdougall, C., Moloney, G., Saul, B., Finnell, J.S., Richardson, K., Petersen, K.M., 2014. Effects of 7 days on an ad libitum low-fat vegan diet: the McDougall Program cohort. Nutr. J. 13.
  36. Barnard, N.D., Scialli, A.R., Turner-Mc-Grievy, G., Lanou, A.J., Glass, J., 2005. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am. J. Med. 118, 991–99.
  37. Spencer, E., Appleby, P., Davey, G., Key, T., 2003. Diets and body mass index in 38,000 EPIC-Oxford meat-eaters, fish-eaters, vegetarians and vegans. Int. J. Obes. 27, 728–734.
  38. Kahleova, H., Matoulek, M., Malinska, H., Oliyarnik, O., Kazdova, L., Neskudla, T., Skoch, A., Hajek, M., Hill, M., Kahle, M., Pelikanova, T., 2011. Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes. Diabet. Med. 28, 549–559.
  39. Toth MJ, Poehlman ET. Sympathetic nervous system activity and resting metabolic rate in vegetarians. Metabolism. 1994;43(5):621-665
  40. Requena, T., Cotter, P., Shahar, D.R., Kleiveland, C.R., Martínez-Cuesta, M.C., Peláez, C., Lea, T., 2013. Interactions between gut microbiota, food and the obese host. Trends Food Sci. Technol. 34, 44–53.
  41. Sanz, Y., Moya-Pérez, A., 2014. Chapter 14: microbiota, inflammation and obesity. In: Lyte, M., Cryan, J.F. (Eds.), Microbial Endocrinology: The Microbiota-Gut-Brain in Health and Disease. Springer, New York.
  42. Jeffery, I.B., O’toole, P.W., 2013. Diet-microbiota interactions and their implications for healthy living. Nutrients 5, 234–252.
  43. Musso, G., Gambino, R., Cassader, M., 2010. Obesity, diabetes, and gut microbiota: the hygiene hypothesis expanded. Diabetes Care 33, 2277–2284.
  44. Verdam, F.J., Fuentes, S., De Jonge, C., Zoetendal, E.G., Erbil, R., Greve, J.W., Buurman, W.A., De Vos, W.M., Rensen, S.S., 2013. Human intestinal microbiota composition is associated with local and systemic inflammation in obesity. Obesity 21, E607–E615.
  45. Zimmer, Carl (20 April 2011). “Bacteria Divide People Into 3 Types, Scientists Say”. The New York Times. Retrieved 21 April 2011. a group of scientists now report just three distinct ecosystems in the guts of people they have studied.”
  46. Arumugam M, Raes J, et al. (April 2011). “Enterotypes of the human gut microbiome”. Nature. 473 (7346): 174–80.
  47. Wu GD, Chen J, Hoffmann C, Bittinger K, Chen YY, et al. (2011). “Linking Long-Term Dietary Patterns with Gut Microbial Enterotypes”. Science. 334 (6052): 105–108.
  48. Keim, Brandon (20 April 2011). “Gut-Bacteria Mapping Finds Three Global Varieties”. Wired Magazine. Retrieved 21 April 2011.
  49. Coghlan, Andy (20 April 2011). “Each human has one of only three gut ecosystems”. New Scientist. Retrieved 21 April 2011.
  50. Benus, R., Van Der Werf, T.S., Welling, G.W., Judd, P.A., Taylor, M.A., Harmsen, H.J.M., Whelan, K., 2010. Association between Faecalibacterium prausnitzii and dietary fibre in colonic fermentation in healthy human subjects. Br. J. Nutr. 104, 693–700.
  51. Jin, C., Flavell, R.A., 2013. Innate sensors of pathogen and stress: linking inflammation to obesity. J. Allergy Clin. Immunol. 132, 287–294.
  52. Matijašić, B.B., Obermajer, T., Lipoglavšek, L., Grabnar, I., Avguštin, G., Rogelj, I., 2014. Association of dietary type with fecal microbiota in vegetarians and omnivores in Slovenia. Eur. J. Nutr. 53, 1051–1064.
  53. Zimmer, J., Lange, B., Frick, J.-S., Sauer, H., Zimmermann, K., Schwiertz, A., Rusch, K., Klosterhalhalfen, S., Enck, P., 2012. A vegan or vegetarian diet substantially alters the human colonic faecal microbiota. Eur. J. Clin. Nutr. 66, 53–60.
  54. Glick-Bauer, M., Yeh, M.-C., 2014. The health advantage of a vegan diet: exploring the gut microbiota connection. Nutrients 6, 4822–4838.
  55. Turner-Mc-Grievy, G., Wirth, M.D., Shivappa, N., Al, E., 2015a. Randomization to plant-based dietary approaches leads to larger short-term improvements in Dietary Inflammatory Index scores and macronutrient intake compared with diets that contain meat. Nutr. Res. 35, 97–106.
  56. Kim, M.-S., Hwang, S.-S., Park, E.-J., Bae, J.-W., 2013. Strict vegetarian diet improves the risk factors associated with metabolic diseases by modulating gut microbiota and reducing intestinal inflammation. Environ. Microbiol. Rep. 5, 765–775.
  57. Li, J., Armstrong, C.L., Campbell, W.W., 2016. Effects of dietary protein source and quantity during weight loss on appetite, energy expenditure, and cardio-metabolic responses. Nutrients 8, 63.
  58. Neacsu, M., Fyfe, C., Horgan, G., Johnstone, A.M., 2014. Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial. Am. J. Clin. Nutr. 100, 548–558.

Drew

Hi! I'm Drew and this is the place where I nerd out about vegan and plant-based diets. I have a BS in Nutrition and Dietetics from the University of Alabama and have taken dozens of classes in areas like organic and biochemistry, food science, medical nutrition therapy, nutritional genomics, and vegetarian diets. I'm still learning every day, and on this blog, I'll be sharing everything I discover about vegan diets as I go.

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