Researchers conducted a study of 244 overweight adults during a 16-week diet. The study was published in Jama Network Open.
The average age of the participants was 53, a time in their lives when many people notice a decline in their metabolism and may have a harder time losing weight as a result.
VEGAN DIET A GOOD WEIGHT-LOSS STRATEGY
Half of the study group was randomly assigned to follow a low-fat vegan diet and was provided with cooking tips. The other half was asked to follow their typical diet without any changes. Both groups kept their exercise habits the same.
The vegan group lost a significant amount of body fat and burnt 14% more calories on average after meals than before switching diets.nParticipants also had a lot of protein on the diet and supplemented with vitamin B12, an essential nutrient that can be hard to get from plant-based foods.
These findings help explain previous studies showing that veganism can be an effective strategy for weight loss. Dr Hana Kahleova, the study’s lead author, said:
“We’ve known for such a long time that a vegan diet helps for weight loss and helps with diabetes, but we haven’t understood the underlying mechanism; why the vegan diet works.”
HEAT-BURNING EFFECT OF VEGAN FOOD
Vegan diets tend to be filled with whole grains, legumes and vegetables. Vegans thus end up eating a lot of fibre, an important nutrient that helps regulate digestion.
Fibre also takes a lot of energy to digest. As the body works to break down fibre it generates heat-burning calories in the process. This is known as the thermic effect of food.
With 53 the average age of participants, Kahleova said: “People think as they age [their] metabolism slows down, but this shows you can turn things around.”
EAT CARBS AND LOSE WEIGHT
Plant-based foods contain a lot of complex carbs which can boost the thermic effect and increase the number of calories you burn while digesting a meal. The diet in the study was 75% carbs, 15% protein and 10% fat.
Participants still lost weight in part due to the thermic effect, but also because all those unprocessed plant carbs are naturally low in calories and high in nutrients. Participants in the study were not asked to restrict calories, but ended up eating an average of 350 calories less each day on a vegan diet.
“Plant-based foods are known to be more satiating and less energy dense. This clearly shows that a vegan diet can help people lose weight even without an intent to reduce calories.”
VEGAN DIET IMPROVES BLOOD SUGAR LEVELS
Participants showed improvements to insulin sensitivity, an important factor in maintaining stable blood sugar levels and preventing type 2 diabetes by the end of the study. Kahleova said: “That’s likely due to the effects of weight loss.
“As we gain weight, our body responds less and less to insulin, becoming insulin resistant. Too much body fat, particularly visceral fat that accumulates around the organs, can cause health issues, including higher risk of type 2 diabetes.”