Veganism and your health
You may lose weight on a vegetarian or vegan diet. One 2016 study (1) conducted a meta-analysis (the highest level of scientific review, see here for details of how we rate the evidence of such reviews) of 12 randomised control trials and found that subjects on a vegetarian diet lost significantly more weight than those in non-vegetarian diet groups. That weight loss was even more significant when it came to vegans and still more pronounced in vegans who also restricted their calories – although it is likely that in the latter category, calorie restriction played a large role in this.
In 2017, researchers from the Department of Experimental and Clinical Medicine at the University of Florence in Italy conducted a weighty systematic review into the association between a vegan diet and chronic diseases (2). The authors crunched the numbers of 96 studies in this top-level review and found that vegan diets were associated with reduced levels of body mass index (BMI), total cholesterol, LDL-cholesterol (supposedly the ‘bad’ cholesterol), and glucose levels in vegetarians and vegans versus omnivores. The study also concluded that vegans had fewer incidences of heart disease and cancer, although the evidence was deemed sketchier for specific types of cancer.
Type 2 diabetes
A number of different studies have shown that vegan and/or vegetarian diets may help with type 2 diabetes. One of the most prominent was published in 2019 (3) when researchers from a number of Italian institutes, including the Italian Society of Diabetology, got together to look into how six months or more of different diets affected diabetes control and management. The team assessed a number of trials on various eating plans including low-carb, macrobiotic, vegan, vegetarian, Mediterranean and intermittent fasting diets and compared them to more traditional low-fat diets. They concluded that vegan, vegetarian and Mediterranean dietary patterns should be used in public health strategies moving forward.
Anyone who’s seen the movie The Game Changers (pictured) will be aware of the growing number of high-level sports personalities who have converted to veganism. Add to those who starred in the film, add the like of tennis superstar Venus Williams, F1 champ Lewis Hamilton, former Premier League striker Jermaine Beckford, ultramarathon legend Scott Jurek and gridiron star and activist Colin Kaepernick and it’s an impressive list.
Anecdotal evidence for their prowess includes reports of reduced inflammation, reduced fatigue and improved strength. The counterbalance to all that is, of course, the number of world stars across all sports who are confirmed omnivores. One review into vegan/vegetarian diets and athletic performance (4) found that:
“Consuming a predominately vegetarian-based diet did not improve nor hinder performance in athletes.”
However, that conclusion was based on just eight identified studies, so the jury remains out on veganism and sporting performance. For those who are interested in following that route, some good advice can be found in this informative article.
When it comes to pregnancy, making sure the baby and mother are both healthy is naturally the main concern. Despite this, there are few studies into how vegan diets may affect pregnancy and gestation. A 2015 systematic review in the International Journal of Obstetrics and Gynaecology (5) found just 21 viable studies for analysis and found the evidence to be inconclusive on whether veganism would harm or help foetal development. As such, the authors concluded that vegan diets were safe in pregnancy, providing attention was paid to certain potential nutritional deficiencies associated with veganism (see below).
A word of caution
It’s tempting given some of the above to think that veganism may be a panacea for a number of different conditions. It’s important though to highlight that some studies have shown that veganism can have unproven, negligible or even detrimental effects.
One systematic review into how different diets could affect rheumatoid arthritis found the studies it assessed were too small or open to bias to come to a conclusion (6) , another found little difference in the gut bacteria of vegans and meat eaters (7). Another recently published review (8) concluded that those who avoided all meat consumption had significantly higher rates or risk of depression and anxiety.
Others, meanwhile, argue that while death rates of vegans/vegetarians compare positively with those of the general population, that other factors might be at play such as high levels of physical activity and low alcohol, cigarette and drug use (9) associated with those who take care of their diet.