Low-carb vegan diets just as healthy as going vegetarian — and better for the planet

TORONTO, Ontario — On the lookout for a fresh diet plan? Researchers from St. Michael’s Hospital report that adopting a low-carb vegan diet offers virtually the same health benefits as going vegetarian. Moreover, the team finds a low-carb vegan diet is also much better for the environment.

Study authors report a low-carbohydrate vegan diet resulted in a much lower potential carbon emission value than a high-carb vegetarian approach to eating. Interestingly, researchers also found that the lower the potential carbon emission value of the diet, the larger the reduction in blood cholesterol. Overall, the research team believes this work showcases the importance of diet regarding both better health outcomes and lower carbon emissions.

“We showed that you actually reduce greenhouse gas emissions, with a diet, that is effective, and that the reduction in greenhouse gas emissions is related to the fall in LDL cholesterol – often called the ‘bad’ cholesterol,” says principal study author Dr. David Jenkins, director of the Clinical Nutrition and Risk Factor Modification Centre and a scientist in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, in a media release. “So as you reduce the impact of your diet on the environment, you also benefit by lowering your cholesterol.”

Vegan dieters saw similar results and lost more weight

Researchers placed the study participants in one of two different plant-based dieting groups. One group had to eat a low-carb vegan diet featuring absolutely no meat, dairy, or eggs — supplemented with a variety of canola oil-enriched breads and high-protein vegan meat alternatives. This diet attempted to recreate popular low carb diets that usually include lots of meat and animal fats using only plant ingredients.

The second group had to follow a vegetarian version of the clinical standard diet for lowering blood pressure, called the Dietary Approaches to Stopping Hypertension diet or “DASH” diet. This type of diet includes egg whites and low-fat dairy, but no meat. Doctors usually prescribe the DASH diet to people with high blood pressure, diabetes, and other cardiovascular diseases. However, the exact diet followed by participants in this study cut out cholesterol sources, differing from the typical DASH diet.

Next, study authors compared the effects of the diets on each person’s health, as well as the carbon emission potential of both diets. To achieve this, they used multiple greenhouse gas emission databases that obtained mean values for each food.

By the end of the three-month experimental period, researchers noted that the two diets resulted in very similar levels of weight loss, lower blood pressure, and reduced blood cholesterol. Study participants on the vegan diet lost 13 pounds, while those on the vegetarian diet lost 11.5. Additionally, dieters in both groups experienced a decline in hemoglobin A1c, a marker of glycemic control.

Your body can adjust to a new diet in 3 months

Dr. Jenkins adds that participants reduced their hemoglobin A1c by roughly one percent, which is the type of reduction produced by most drugs. This suggests these diets had an almost drug-like effect.

While this study only tracked dieters for three months, earlier projects including participants with high cholesterol have shown that people can successfully maintain weight loss for much longer than three months. Researchers say this means that three months is likely an adequate amount of time for one’s metabolism to adapt to a new diet.

All study participants were healthy at the start of the experiment, which means further reductions in risk factors like blood cholesterol and blood pressure would have been difficult. However, participants did display declines in relevant risk factors on both the vegan and vegetarian diets.

“We have got to start changing the way we’re doing things in life,” Dr. Jenkins concludes. “This is just a small example that you can do it, it can be healthy. It is palatable. And you can reduce at least one risk factor, too.”

The study is published in the American Journal of Clinical Nutrition.

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