Health benefits of a plant-based diet

Nutrition researcher Joshua Gibbs outlines the health benefits of a plant-based diet and why it could help you live longer

Reading time: 5 minutes

Touted for their environmental benefits, plant-based diets are becoming increasingly popular amongst young adults. They are broadly defined as diets that emphasise the consumption of plant-based foods and exclude or limit the consumption of most or all animal products.

Healthy plant-based diets focus on maximising fruits, vegetables, wholegrains, legumes, nuts and seeds and limiting processed foods such as refined grains, desserts, and sugar-sweetened drinks. Vegan, vegetarian, Mediterranean, and flexitarian diets are examples of some popular plant-based diets. The latest science suggests that following a plant-based diet may lead to living a longer life. In a study published in Public Health Nutrition, researchers found that those eating the most plant foods and the least animal foods had a 25% lower risk of dying from all causes compared with those eating the least plant foods and the most animal foods. Eating lots of healthy plant-based foods boosted the effect, lowering the risk of death to 36%. Additionally, those who ate the highest amount of unhealthy plant-based foods had a 41% increased risk of dying from all causes.

Here, we explore why those following plant-based diets may live longer and whether you need to completely cut out meat to reap the benefits.

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Eating a plant-based diet could help you maintain a healthy weight

Eating a plant-based diet may slash your obesity risk. It appears that the more animal-based foods people eat, the higher their Body Mass Index (BMI) tends to be. In a study published in the International Journal of Obesity, researchers found that vegans and pescatarians gain significantly less weight year on year compared with meat eaters. Another study found that each additional 250 grams per day of meat consumed led to a 2 kg greater weight gain over five years. Additionally, a study in Nutrients found that those who ate the highest amount of healthy plant foods and the least animal foods had a 69% lower risk of developing obesity.

Eating more plants and less meat may help you to shake off any excess weight. A randomised controlled trial published in Nutrition & Diabetes put people on a healthy plant-based diet with no calorie restrictions and after six months they lost 12kg on average. This is the greatest weight loss ever recorded for a dietary intervention with no energy restrictions.

Plant-based foods are thought to assist weight loss through multiple pathways. Firstly, fruits and vegetables have very high water content which makes them filling and satiating. This leads to fewer calories being consumed overall. Secondly, plant-based foods are packed with fibre that feeds our good gut bacteria, which turn down our appetite and boost our metabolism and rate of fat burning. Thirdly, plant-based foods contain unique compounds, such as thylakoids in leafy greens, that can boost the production of appetite suppressing hormones.

Plant-based diets may prevent type 2 diabetes

Obesity is a major risk factor for type 2 diabetes as fatty tissue makes cells more resistant to insulin and its effects. Since plant-based diets slash obesity risk it’s no surprise that they also cut down the risk of developing type 2 diabetes. A study published in Diabetes Care found that type 2 diabetes was only present in 2.9% of vegans, whereas it was present in 7.6% of non-vegetarians. Another study found that vegans had less than half the risk of developing type 2 diabetes than non-vegetarians. A different study found that each 10% increase in plant-based diet index score resulted in a 7% lower type 2 diabetes risk. This was mainly due to increases in healthy plant[1]based foods, not changes in animal-based foods. On top of preventing type 2 diabetes, plant-based diets may also be helpful in the treatment and management of the disease. A meta-analysis exploring data from six studies found that vegetarian diets significantly improved glycaemic control.

Eating a plant-based diet may lower your blood pressure

Hypertension or high blood pressure is the number one risk factor for death globally. Fortunately, our diets can make a big difference. A large cohort study found that meat consumption increases the risk of high blood pressure independently of low fruit and vegetable consumption. Considering this, it’s no shock that vegans seem to have the lowest rates of hypertension. A study published in Public Health Nutrition found that vegans had about half the odds of developing high pressure than meat eaters. A study published in the Journal of Hypertension found that switching to a plant-based diet can significantly lower your blood pressure even with the inclusion of some animal products.

A plant-based diet may prevent cardiovascular disease

High cholesterol can lead to the formation of fatty plaques in our arteries which restrict blood flow and potentially lead to heart attack and stroke. One of the main causes of high cholesterol is eating too much saturated fat. Saturated fat is found in high amounts in meat and high-fat dairy products. A meta-analysis of 19 clinical trials found that vegan and vegetarian diets significantly lower bad LDL cholesterol levels. This, combined with the lower body weight and blood pressure associated with plant-based diets, leads to a lower risk of cardiovascular disease. A meta-analysis published in Nutrients found that those following plant-based diets had a 16% lower risk of cardiovascular disease and an 11% lower risk of heart disease. In a study published in Neurology, those who ate the highest amount of healthy plant foods had a 10% lower risk of stroke. In the Lyon Diet Heart Study, those randomised to a plant[1]based Mediterranean diet experienced 72% fewer cardiovascular events than those following a Western diet.

A plant-based diet may help prevent cancer

As we’ve covered, following a plant-based diet can have a plethora of health benefits and the latest research suggests this may also include cancer prevention. In a study published in the International Journal of Cancer, those who ate high amounts of plant-based foods and low amounts of animal-based foods had a 15% lower risk of overall cancer. Another study found that vegans had a 19% lower risk of all cancers. A meta-analysis exploring six studies found that semi-vegetarians had a 14% lower risk of colorectal cancer and that pescatarians had a 33% lower risk. The findings on plant-based diets and breast and prostate cancer risk are mixed. More research is needed in these areas.

Simply put: to live longer, eat more fruits and veg, and less meat and junk food.

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