Plant-based diets, which focus on fruits, vegetables, grains, and pulses, can be a great tool for eating healthy. In a small study in New Zealand, researchers randomly assigned overweight and obese adults to either a whole foods plant-based diet (with vitamin B12 supplementation) or a control group with no special diet for six months. Although the plant-based diet was not calorie restricted, those in the diet group lost on average 24 pounds after one year, and after excluding dropouts (49 of the 65 participants completed the study), the diet group also significantly improved their cholesterol.
Nutrition & Diabetes. 2017 Mar 20;7(3):e256. (Wright N et al.)

Despite heavy marketing of the Paleo diet and lifestyle, very little is known about what our early human ancestors actually ate. To learn more about their diets, scientists in Australia studied the DNA of dental plaque from the teeth of Neanderthals (relatives of early humans) who went extinct about 40,000 years ago. While there was evidence of a meat-based diet (including wooly rhinoceros and sheep) in what is today Belgium, the Neanderthal diet in what is today Spain indicated a vegetarian diet, including mushrooms pine nuts, and moss.
Nature. 2017 Mar 8. [Epub ahead of print] (Weyrich LS et al.)

Soy foods (like tofu, edamame, or soy milk) have a complicated relationship with breast cancer, since soy has estrogen-like properties. To see if eating isoflavones (the major estrogen-like compound in soy) relates to breast cancer outcomes, researchers analyzed the eating habits and health outcomes of more than 6,000 newly-diagnosed breast cancer patients (all women) in the US, Canada, and Australia. Scientists found that women eating the most isoflavones (the amount in at least ¼ cup soymilk per day) were less likely to die over the 9-year study period, but the results were only statistically significant in women with hormone-receptor-negative breast cancers (the breast cancers unlikely to respond to hormonal therapy).
Cancer. 2017 Mar 6. [Epub ahead of print] (Zhang FF et al.)

Legumes, the food group that includes beans, peas, lentils, and peanuts, are central to traditional diets around the world. To see how legumes relate to heart health, scientists reviewed 14 studies with 367,000 participants in both Mediterranean and non-Mediterranean populations. They found that a high intake of legumes (roughly less than one serving per day, or three to four servings per week) was associated with a 6% lower risk of any heart disease, and a 10% lower risk of coronary heart disease specifically. However, no association was found between legume consumption and stroke risk.
Journal of Public Health Nutrition. 2017 Feb;20(2):245-254. (Marventano S et al.)

More and more professional athletes are embracing plant-based diets, and for a good reason.  To see how diet relates to athletic abilities scientists analyzed the strength and oxygen uptake of 27 vegetarian athletes and 43 omnivorous athletes. They found that while there was no significant difference in strength (measured by torque) between vegetarian and non-vegetarian athletes, female vegetarian athletes had better oxygen uptake (measure by VO2 max) than their non-vegetarian counterparts (no significant difference for males). The authors conclude that “following a vegetarian diet may adequately support strength and cardiorespiratory fitness development, and may even be advantageous for supporting cardiorespiratory fitness.”
Nutrients. 2016 Nov 15;8(11). pii: E726. (Lynch HM et al.) 

Plant-based diets are shown to be more sustainable, but nutrition researchers want to know if they are as satiating as meat-centric meals. In a randomized, double-blind study, 43 healthy young men were given a patty made from either veal and pork (high protein), fava beans and split peas (high protein), or fava beans and potatoes (low protein). The participants rotated through each of the 3 meals (with a 2-week washout in between each one), serving as their own controls. Although the fava and split pea patty was rated as less palatable than the other two meals, it proved to be the most satiating, with participants reporting less hunger and appetite afterwards, and participants didn’t need to eat as much at the following meal to feel full. While both the fava/pea patty and veal/pork patty were both high protein, the additional fiber in the fava/pea patty could also have contributed to the fullness.
Food and Nutrition Research. 2016 Oct 19;60:32634. (Kristensen MD et al.)

Plant-based diets show promise for a number of . Using more than 20 years of health and nutrition data, researchers scored the diets of more than 200,000 U.S. adults to see how closely they aligned with a plant based diet (mostly plant foods, minimal animal foods), a healthy plant based diet (emphasizing whole grains, fruits, vegetables, nuts, and legumes), or an unhealthy plant based diet (emphasizing refined grains, juice, and sweets). Plant-based diets were associated with a 20% lower risk of type 2 diabetes, while healthy plant based diets indicated an even greater risk reduction (34%). On the other hand, unhealthy plant based diets were linked with a 16% increased risk of type 2 diabetes. The researchers note that “plant-based diets need not completely exclude animal foods,” as those with the highest healthy plant based diet scores averaged 4 servings of animal foods per day, compared to 5-6 servings per day in those with the lowest scores. 
PLoS Medicine. 2016 Jun 14;13(6):e1002039. (Satija A et al.)

Plant-based diets are linked with numerous health benefits, but you must take care to choose healthier plant foods close to nature, that haven’t been refined or include lots of added sugars. To investigate the importance of this point, Harvard researchers analyzed the eating habits of 195,727  adults across three large cohorts, and tracked their health records for decades. Eating a healthy plant based diet (with whole grains, fruits, vegetables, nuts, legumes, vegetable oils, tea, and coffee) was linked with a 34% lower risk of type 2 diabetes, while eating a less healthy plant based diet (with fruit juice, sugary drinks, refined grains, potatoes, and desserts) was linked with a 16% higher risk of diabetes.
PLoS Medicine. 2016 Jun 14;13(6):e1002039. (Satija A et al.)

Forests are an important harbor of biodiversity and carbon storage, so cutting into forests to create more cropland could be very harmful to the ecosystem. To see how we can feed a growing world without cutting into forests, Austrian researchers analyzed 500 different scenarios with varying levels of cropland expansion, dietary patterns, and crop yields.  They found that “a large range of options exist to feed a no-deforestation world,” by 2050, but greatly varied based on what types of foods we’d choose to eat. For example, their models found that if the current North American diet (lots of meat and highly processed foods) continues to expand globally, only 15% of the scenarios involving this eating pattern are feasible. However, “all vegan scenarios and 94% of the vegetarian scenarios are feasible,” indicating the overall sustainability of plant based diets.
Nature Communication. 2016 Apr 19;7:11382. (Erb KH et al.)

Dietary changes are a key target in obesity prevention programs, so many foods are being studied for their affect on body weight. To see if eating more pulses (the food group that includes beans, peas, lentils, and chickpeas) might help reduce obesity, researchers analyzed 21 randomized control trials looking at pulses’ role in weight, body fat, and waist circumference in overweight and obese adults. Diets that included dietary pulses did not significantly reduce waist circumference. There was a trend in reduction of body fat (-0.34%), but it was not significant as well. Overall, the researchers found that those eating about 1 serving of pulses per day lost, on average, about 0.75 pounds over six weeks. Not surprisingly, results were stronger in weight loss diets (3.8 pounds over 6 weeks) than weight maintenance diets (0.6 pounds over 6 weeks). Although the weight loss was small, this study indicates that a modest serving of pulses may help produce weight loss, even without cutting calories.
The American Journal of Clinical Nutrition. 2016 Mar 30. [Epub Ahead of Print] (Kim SJ et al.)

To determine if vegetarian diets might be useful for weight loss, Harvard researchers analyzed results from 12 different clinical trials encompassing 1,151 people. Those assigned to vegetarian diets lost 4.5 pounds more compared to those assigned to a non-vegetarian control diet, regardless of whether or not calories were restricted. Participants assigned to vegan diets (excluding all animal products) lost more weight (5.6 pounds) than those assigned to lacto-ovo vegetarian diets (3.2 pounds). The diets ranged from 9 weeks to 74 weeks, with a median duration of 18 weeks. The scientists conclude that “Vegetarian diets appeared to have significant benefits on weight reduction compared to non-vegetarian diets.”
Journal of General Internal Medicine. 2016 Jan;31(1):109-16. (Huang RY et al.)

Over a quarter of cancer cases in men are prostate cancer, so dietary strategies to prevent prostate cancer could benefit many. To study this relationship, scientists analyzed the diet and prostate cancer diagnoses in a group of over 26,000 men for nearly 8 years. They found that vegan diets (diets that exclude all animal products, including dairy and eggs) were linked with a 35% lower risk of prostate cancer than non-vegetarian diets that included meat, poultry, fish, dairy, and eggs. Other vegetarian diets (that include dairy and eggs) did not show a statistically significant protective effect.
American Journal of Clinical Nutrition. 2016 Jan;103(1):153-60. (Tantamango-Bartley Y et al.)