Chew on This

Men Admit Vegan Meals Left Them Fuller, Medical Study Says

Test sample was small but the implications are huge: Non-animal meals triggered higher release of ‘satiety’ hormones

A vegan offering
Tomer Appelbaum

Veganism is hugely popular in Israel. The U.K. newspaper The Independent even dubbed Tel Aviv the “vegan capital of the world.” Now, a new if small-scale study published in the journal Nutrients by an American-Czech team debunks a key argument by the carnivores who remain among us: that without meat, they just don’t feel full.

Leaving one’s subjective mind and mulishness out of it, biochemically speaking, plant-based meals left men feeling fuller than non-vegan meals did, claim Dr. Hana Kahleova and colleagues at Physicians Committee for Responsible Medicine.

Vegan meals achieved this by inducing higher levels of “beneficial” gastrointestinal hormones than non-vegan meals, the team says. Whether vegan meals have the same effect on women was not tested in the study.

Gastrointestinal hormones are produced in the stomach, pancreas and small intestine, and are secreted into the bloodstream. Triggered by different things – everything from the thought of food to actually eating, to specific flavors – the hormones govern a host of bodily functions, from digestion to nutrient absorption to the suspicion that one should stop eating.

Much about these hormones remains mysterious, as does the reason why some people think they need meat to feel full.

“Our results indicate there is an increase in gut hormones and satiety, following consumption of a single plant-based meal with tofu when compared with an energy- and macronutrient-matched processed-meat meat and cheese meal, in healthy, obese and diabetic men,” the authors, led by Marta Klementova of the Czech Institute for Clinical and Experimental Medicine, wrote.

So, biochemically, vegan meals left the test subjects feeling fuller than non-vegan meals did, the study found.

Gastrointestinal hormones, released in keeping with what we eat, regulate our glucose metabolism and secretion of insulin, our energy balance, and that sense of satiety. In other words, they play a role in weight management, Kahleova explains.

Eating vegan can keep us feeling full longer, she concludes, adding: “The fact that simple meal choices can increase the secretion of these healthy hormones has important implications for those with type 2 diabetes or weight problems.”

The study group was just 60 men, of whom 20 were obese, 20 had type 2 diabetes and 20 were healthy. The researchers checked hormone levels in the men after vegan meals, and after meals containing meat and cheese. The vegan and non-vegan meals contained the same amount of calories and ratio of macronutrients, the team explains.

In all three types of men, the vegan meal drove higher gastrointestinal hormones than the non-vegan meal. Also, importantly, men in all three groups self-reported that the vegan meal made them feel fuller than the non-vegan meals.

Myriad explanations come to mind for the self-reported satiety. The men may have preferred the taste of the non-vegan meals and felt like eating more, while eating just so-much of the vegan offering may have sufficed to make them “feel full.” But the researchers suggest a more satisfying explanation: That vegan food is fiber-rich, which contributes to the sense of satiety.

In any case, the study casts intriguing light on claims that vegan meals don’t make one feel full.

In 2017, over 5 percent of Israeli adults defined themselves as vegan, according to the Central Bureau of Statistics. That compares with somewhere between 1 to 2 percent in 2012. If vegetarians are included, the figure rises to about 10 to 13 percent.

Calling Israel the “vegan capital” of anything is a stretch, though. It is true that data on “How many vegans/vegetarians, etc.” are hard to compare, not least because definitions vary.

Some countries such as the United States define vegan just to mean “no meat, eggs or dairy,” but allows honey, while other places have stricter definitions. There is also the issue of embarrassment. Even vegan advocates admit there is a massive lapse rate from veganism and vegetarianism, which doesn’t help nail down stats.

But roughly speaking, the most vegetarian/vegan country of them all is India, with its vast population that eschews meat of all kinds (but not necessarily animal products). Anywhere from 30 to 40 percent of Indians are vegetarian or vegan.

A host of European countries, including Austria and the Netherlands, run vegetarian “rates” of about 5 percent – whether out of concern for animal welfare or their own health. Even the United States, home of the hamburger, cheese steak and bacon worship, has a roughly 7 percent rate of vegetarians.

One famous vegan is Bill Clinton: Once a carefree carnivore, now the former U.S. president eschews the animal and doesn’t even eat eggs or dairy. However, as he told CNN’s Wolf Blitzer in 2010, he supplements his diet of “beans, legumes, vegetables and fruits” with protein supplements, which isn’t a solution for the impoverished vegan. Clinton loves animals but he did it mainly because the cholesterol was killing him, he explained.

Perhaps protein will become more affordable, with the advent of mass-scale bug farming. And for what it’s worth, as the world population grows, while meat lovers may have to scale down their sights from cows to grasshoppers, vegans can look toward spirulina – an algae that has conveniently demonstrated a propensity to grow on wastewater and is protein-rich to boot. The question is: Who would want to eat it, let alone a lot of it? Maybe it's all about the delivery. A bunch of Israeli students at Haifa’s Technion recently turned spirulina into falafel and won an award for it, no less.