News

Plant-Based Diet May Boost Metabolism, Lower Cholesterol, and Aid Weight Loss

vegan bowl of food

Getty Images / istetiana

Key Takeaways

  • Plant-based eating revolves around consuming foods such as fruits, vegetables, whole grains, beans, and nuts, and avoiding animal products and refined, processed foods.
  • A recent study found that eating a plant-based diet can help boost metabolism, lower cholesterol, and support weight loss.
  • Switching to a plant-based way of eating now is easier than it ever has been with the wide availability of resources and plant-based alternatives.

Consuming a more plant-based diet may help increase your metabolism, lower your cholesterol, and aid in weight loss, according to a 2020 study published in JAMA Network Open.????

“This study further supports the efficacy of plant-based diets in weight loss and healthy lifestyle. There are many other studies that have found similar benefits,” says Sharon Palmer, MSFS, RDN, a plant-based dietitian, blogger, author, and professor.

What Is a Plant-Based Diet?

Put simply: a plant-based diet includes all whole plant foods from vegetables, fruits, and whole grains to beans, legumes, nuts, seeds, and herbs and spices. People eating plant-based avoid meat, dairy, eggs, and all other animal products. They also avoid processed foods.

This varies slightly from a vegan diet in which people might also consume processed “vegan” foods, such as vegan ice cream, soda, et cetera, which are eaten minimally, if at all, on a plant-based diet.

What the Study Found

This study measured how a low-fat, plant-based diet affects body weight, insulin resistance, metabolism, and intramyocellular and hepatocellular (muscle- and liver-related) lipid levels in overweight adults.????

The 244 participants had BMIs between 28 and 40 with no prior history of diabetes, smoking, alcohol or drug use, pregnancy, or use of a plant-based or vegan diet. Nearly half the participants were white, 87% were female, and the average age was 54.

Participants were assigned randomly in a one-to-one ratio to the control group, which was told to make no diet changes, or to the intervention group, which was asked to follow a low-fat, plant-based diet.

Both groups minimized alcohol consumption and maintained their exercise habits and medications (unless otherwise instructed by their personal doctor).

The plant-based diet included veggies, fruits, grains, and legumes, eliminated all animal products and added fats, and supplemented vitamin B12. This group also participated in weekly instruction and cooking demonstrations classes and received small food samples and printed materials.

After four months, the plant-based group increased their post-meal calorie burn by nearly 19%, reduced their LDL cholesterol by 19.3 mg/dL and total cholesterol by 23.2 mg/dL, and lowered overall body weight by about 13 pounds. There were no noteworthy changes in the control group.????

“Plant-based diet intervention groups [in general] have reported greater diet satisfaction than control groups, as well as improved digestion, increased energy, and better sleep, and significant improvement in their physical functioning, general health, vitality, and mental health,” says Michael Greger, MD, FACLM, the founder of NutritionFacts.org and a New York Times bestselling author and internationally recognized speaker on nutrition, food safety, and public health issues.

Limitations

There were some limitations to this study, namely that dietary intake was self-reported. That being said, the reported changes in diet were reflected in weight and plasma lipid levels.

In addition, “health-conscious participants may not be representative of the general population but may be representative of a clinical population seeking help for weight problems or type 2 diabetes,” say the study authors.?????

The study only took place over 16 weeks, so long-term effects could not be measured. Lastly, researchers could not separate specific effects of the low-fat, plant-based diet from the weight loss it caused.

Benefits of Eating Plant-Based

There are a multitude of benefits to eating a plant-based diet, such as increased metabolism, weight loss help, and reduced risk of heart disease and heart disease reversal.

“I have also seen hundreds of clients in my nutrition practice experience extraordinary (and sometimes unexpected) side effects of switching to a plant-based diet, including overcoming life-long asthma, eczema, reductions of acne, aches, and pains,” says Julieanna Hever, MS, RD, CPT, a plant-based dietitian and author based out of Los Angeles.

May Increase Metabolism

The hypothalamus, a small area in the middle of our brain, regulates metabolism. It helps control appetite so we eat the optimal amount of food, Greger says.

By increasing our metabolism, we increase the rate at which we convert food into energy. Slow metabolism reduces this rate, thus making it harder to lose weight.

Everyone has their own metabolic rate—those with high metabolism require more energy to fuel their body and maintain their weight, while the opposite applies to those with low metabolism, Palmer says.

“In this study, the control group didn’t change their diet,” Palmer explains. “If they were eating a typical Western diet, that would mean a highly refined diet with foods that are rapidly digested and absorbed in the body.

If the plant-based diet were based on unrefined foods, previous research has found that unprocessed whole plant foods have a much greater thermic effect—meaning they take energy to be utilized in the body. Studies have even shown a difference between things like whole nuts vs. ground nuts—eating them whole provides net fewer calories because of digestion."

May Aid With Weight Loss

The study found that eating plant-based led participants to lose 13 pounds on average. The reasons for this may be that a plant-based diet is typically high in fiber, which helps you feel fuller longer.??

“It is also naturally lower in fat. It has lower calorie density—which means that you can get full on a lower amount of calories, yet those calories have a big bang for their buck. In a small amount of calories, you are getting a lot of nutrients," Palmer says.

One such way eating plants can help with weight loss is through “preloading” with negative calories. Greger describes a set of experiments at Penn State where study subjects were served pasta and told to eat as much as they’d like, which was approximately 900 calories' worth.?????

The next time, researchers gave them a 100 calorie salad composed mainly of lettuce, cucumbers, tomatoes, carrots, and celery to eat before digging into the pasta meal. They wanted to find out if subjects would then eat the same amount of pasta or less.

“In fact,” Greger says, “the subjects ate more than 200 fewer calories of pasta after the salad course. They took in 100 calories from the salad and left off 200 calories of pasta. In essence, the salad had negative 100 calories. The Penn State study showed that preloading with vegetables can effectively subtract 100 calories out a meal, illustrating how weight can be lost by eating more food.”

The same results applied with most fruits and vegetables, but not dinner rolls or salads laden with fatty dressings and cheese.

May Reverse Heart Disease

A plant-based diet may also have cardiovascular benefits, according to Hever. A plant-based diet is the only eating pattern that has been associated with reversing advanced-stage cardiovascular disease and type 2 diabetes.??????

Heart disease is the number one killer in the United States, with one in every four deaths attributed to it per year.?????? Coronary artery disease is the most common type, causing decreased blood flow to the heart.????

Michael Greger, MD

The three boosters of bad cholesterol—the number-one risk factor for our number-one killer [heart disease]—all stem from eating processed foods and animal products.

— Michael Greger, MD

Plaque, made up of primarily cholesterol, accumulates in the walls of the arteries that supply the heart with blood, causing them to narrow. If not reversed, this can cause a partial or total blockage of blood flow to the heart over time.??????

A landmark study by Dr. Dean Ornish found that by simply making diet and lifestyle changes, chest pain diminished, blood flow to the heart improved, and after a year, severely blocked arteries reopened.?????? These results have been replicated.???? Compliant patients are still thriving today.??

To reduce LDL (or “bad”) cholesterol levels, Greger says to reduce the intake of trans fat (found naturally in meat, dairy, and processed foods), saturated fat (which is primarily in animal products and processed foods), and dietary cholesterol (which occurs in animal products, especially eggs).

“The three boosters of bad cholesterol—the number-one risk factor for our number-one killer—all stem from eating processed foods and animal products,” he says. “If that’s all a whole-food, plant-based diet could do—reverse our number-one killer—shouldn’t that be the default diet until proven otherwise? The fact it may also be effective in preventing, treating, and arresting other leading killers seems to make the case for plant-based eating simply overwhelming.”

Downsides of Plant-Based Eating

The experts interviewed for this article largely agreed that there are little to no downsides to eating plant-based. That being said, switching to plant-based eating does typically require a transition period, which can be difficult for some.

In addition, Palmer says that if you don’t plan what you eat effectively, you run the risk of not getting enough of the nutrients your body needs to function properly. It’s important to eat a wide variety of plant-based foods and to supplement with a B12 vitamin, which is neither produced by the body nor found naturally in plant-foods.??

Protein consumption is also often a concern; however, there are plenty of plant-based sources of protein, including quinoa, tofu and other soy products, nuts, and beans.

How to Start Eating Plant-Based

If you’re interested in switching to a plant-based diet, start simple. Try incorporating more plant-based meals into your weekly meal plan. Swap red meat for beans on your dinner plate. Replace dairy milk with milk alternatives like soy, oat, almond, or hemp.

“Take a one-week challenge,” Palmer suggests. “Try to include a few more plant-based foods prior to the challenge to get ready. Make sure that your pantry is stocked and that you understand the basics of how to plan a healthy plant-based diet.”

Be sure to confer with your doctor before making any drastic lifestyle or diet changes, especially if you are taking any medications or are at risk for developing any diseases.

What This Means For You

Consuming a diet full of whole, plant-based foods may be the key to lowering cholesterol, reducing the risk of and reversing heart disease, speeding up metabolism, and losing weight.

Talk to your healthcare provider before making any drastic changes to ensure you are getting all the nutrients you need. And of course, listen to your body. With the rise in popularity of plant-based eating and alternatives, switching to a plant-based way of eating is easier than it has been in the past. 

“We should eat real food that grows out of the ground, natural foods that come from fields, not factories, gardens, not garbage—a diet centered around whole plant foods,” Greger concludes.

Was this page helpful?
Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Kahleova H, Petersen KF, Shulman GI, et al. Effect of a low-fat vegan diet on body weight, insulin sensitivity, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults: a randomized clinical trial. JAMA Netw Open. 2020;3(11):e2025454. doi:10.1001/jamanetworkopen.2020.25454

  2. Rolls BJ, Roe LS, Meengs JS. Salad and satiety: energy density and portion size of a first-course salad affect energy intake at lunch. J Am Diet Assoc. 2004;104(10):1570-1576.?doi:10.1016/j.jada.2004.07.001

  3. Tuso P, Stoll SR, Li WW. A plant-based diet, atherogenesis, and coronary artery disease prevention. Perm J. 2015;19(1):62-67. doi:10.7812%2FTPP%2F14-036

  4. Centers for Disease Control and Prevention. Heart disease facts. Updated September 8, 2020.

  5. Centers for Disease Control and Prevention. Coronary artery disease (CAD). Updated December 9, 2019.

  6. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease?. Lancet. 1990;336(8708):129-133. doi:10.1016/0140-6736(90)91656-u

  7. Physicians Committee for Responsible Medicine. Heart disease: Boost heart health with a plant-based diet. 2020.

  8. Craig W. Nutrition concerns and health effects of vegetarian diets. Nutr Clin Pract. 2010;25(6):613-20. doi:10.1177/0884533610385707