Many weight-loss plans promote eating more protein and reducing or nixing carbohydrates. However, if you’re trying to lose weight, evidence suggests a plant-based approach — which tends to be higher in carbs— may be helpful. On a plant-based plan, the emphasis is on whole or minimally processed plant foods, and animal foods, if eaten, are consumed in smaller portions or less frequently. Here’s why you should consider a plant-based diet for weight loss.
The case for plant-based diets and weight loss
Though high-protein diets are often touted for weight loss, some studies point to higher body weights among meat-eaters. While animal proteins contribute to satiety, they may also be higher in calories, making it harder to produce the calorie deficit needed for weight loss. In fact, one study that looked at five-year weight changes among more than 370,000 adults found that total meat, red meat and poultry consumption were associated with weight gain over the study period, even after adjusting for factors such as exercise. The study suggests that consuming about nine ounces of meat per day could contribute to a four-and-a-half pound gain over five years. While this research doesn’t show that eating animal protein causes weight gain, it does point out a flaw in the thinking that eating meat is a definitive weight-reducing strategy.
Additionally, a 2018 review of almost a dozen studies found that when compared to typical dietary advice for diabetes, a plant-based diet was tied to better physical and emotional well-being, including better weight-loss outcomes, among participants. Another 2020 review found that, for the most part, transitioning from an omnivore diet to a plant-based diet was linked to weight loss.
How plant-based diets help with weight loss
1. Plant-based diets help produce a calorie deficit
There are many factors involved in weight loss, but one thing’s for sure: You need to be in a calorie deficit to lose weight. And a plant-based diet may make this easier because plant foods generally contain fewer calories per bite than animal foods. For example, the average calorie range per pound of lean meat is 600 to 800 calories — about 100 calories more, on average, than the same quantity of beans. Research has found that people generally eat the same weight of food at meals, so by eating larger amounts of plant foods, you can enjoy the same volume of food for fewer calories.
A 2021 study that compared a plant-based, low-fat diet to an animal-based keto diet found that when people were allowed to eat as much as they were hungry for, they ate almost 700 fewer calories per day when eating the plant-based diet compared to the keto diet. This suggests that people felt fuller on the plant-based diet, and therefore, naturally ate less.
These results are in line with other research, too. A 2016 review that pooled data from 21 trials found that adding a serving of pulses, like chickpeas, to people’s daily menu was linked to weight loss, even when there was no intentional calorie reduction. Put simply, these foods curb your appetite by slowing the rate at which food empties your stomach and stimulating the secretion of hormones that tell you’re full. In essence, they may help prevent overeating without restricting calories.
2. Plant-based diets are full of fiber
Fiber is a buzzword in weight loss because fiber-rich foods are known to promote fullness. Instead of cutting portion sizes of higher-calorie foods, it may be more manageable and sustainable to eat substantial portions of fiber-rich plant foods. But fiber may influence weight loss in other ways, too. For example, upon eating fiber-rich foods, the bacteria in your gut produce short chain fatty acids, which trigger the release of appetite-reducing hormones. This means fiber-filled foods work doubly hard at controlling your appetite.
It’s estimated that 95% of Americans don’t meet their daily fiber targets of 25 grams per day for women and 38 grams per day for men. Since fiber is only found in plant foods, transitioning to a wholesome plant-based diet for weight loss will automatically supply more of this nutrient.
3. Plant-based diets promote insulin sensitivity
Insulin’s main job is to keep blood sugar levels in a healthy range by ushering glucose in your blood to your cells to be used as energy. But it also has a backup plan to provide energy when your cells run out of the quick-acting form. That plan is to store some of this fuel as fat. At the same time, high insulin levels prevent the breakdown of fat, enabling it to build up in cells. For a variety of reasons, when your cells become resistant to insulin’s actions, weight gain is more likely to occur.
Since carbohydrates get converted to glucose, they’re commonly considered the main culprit in insulin resistance and weight gain, but this isn’t necessarily the case. While carbs in the form of dessert, sugary cereals, and white bread may impair insulin sensitivity, evidence suggests that emphasizing plant-based, fiber-filled carbohydrates can reduce insulin resistance and promote a healthier body weight.