Unless you have celiac disease, you might want to rethink that gluten-free diet. In a study of more than 100,000 US adults without celiac disease, followed for more than 25 years, researchers found that eating gluten was not related to heart disease risk. In fact, the researchers caution that avoiding gluten may result in eating fewer whole grain foods, which may in turn pose a risk for heart disease.
BMJ. 2017 May 2;357:j1892. (Lebwohl B et al.)

Whole grains have long been associated with chronic disease prevention in adults, but research suggests that children may benefit as well. In this study, researchers analyzed the 7-day food records of more than 700 Danish children and confirmed whole grain intake by also taking biomarkers of whole wheat and rye intake. They found that whole grains and fiber were linked with lower levels of serum insulin, indicating healthier blood sugar management. Additionally, oats were linked with less body fat, and lower systolic blood pressure (the first number in your blood pressure reading), insulin, and LDL (bad cholesterol).
Journal of Nutrition. 2017 May 1;147(5):816-824. (Damsgaard CT et al.)

Very low carbohydrate “keto” diets can increase oxygen uptake (VO2 peak). However, this doesn’t necessarily translate to an improvement in athletic performance, and may be detrimental. In this study of 21 race walkers, researchers assigned them to a very low carb “keto” diet, or 2 different types of high carb diets. In the keto diet, the participants experienced reduced economy, meaning their bodies required more oxygen at a given speed, despite their increased VO2 peak. This translated to no improvement in the keto diet group speed, with 5.3-6.6% improvements in speed for the high carb diet groups.
The Journal of Physiology. 2017 May 1;595(9):2785-2807. doi:10.1113/JP273230. (Burke LM et al.)

Dementia is a serious neurological disease, so preventive measures are an important area of research.  In a study of 5,907 adults, researchers analyzed whether the Mediterranean diet and/or the MIND diet  (a diet similar to the Mediterranean diet, full of “brain-healthy” foods like leafy greens, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine) have an effect on cognitive performance. Researchers found that those most closely following the Mediterranean Diet had 35% lower odds of having poor cognitive performance (assessed through tests of memory and attention), when compared to those not following a Mediterranean Diet. Results were similar for the MIND diet, probably because there is so much overlap in these two eating patterns.
Journal of the American Geriatrics Society. 25 April 2017. [Epub ahead of print.]  (McEvoy CT, et al.)

Even if you don’t live in the Mediterranean, you can still follow a Mediterranean diet pattern emphasizing healthy foods like fish, whole grains, legumes, and olive oil. In a study of 1,194 Puerto Rican adults in the U.S., researchers analyzed their diets using several different health scores and also collected health measurements from the participants to look for relationships between diet and cardiometabolic health. Those whose diets most closely aligned with a Mediterranean diet were significantly more likely to have smaller waist sizes, a lower BMI, lower levels of inflammation (as measured by C-reactive protein), and lower levels of insulin resistance. The DASH Diet score and Healthy Eating Index 2005 score were not significantly associated with any health measurement, while the Alternative Healthy Eating Index was only weakly associated with some positive health markers.
The Journal of Nutrition. 2017 Apr;147(4):661-669. doi: 10.3945/jn.116.245431. Epub 2017 Mar 8. (Mattei J et al.)

Although food traditions vary from country to country, many traditional healthy diets are rooted in wholesome plant foods like fruits, vegetables, and whole grains. In a study of 1404 people who had been diagnosed with colorectal cancer at least six years prior, researchers analyzed their eating patterns based on how closely they aligned with a Mediterranean diet (fruits, vegetables, grains, unsaturated fats, legumes, moderate alcohol) and a healthy Nordic diet (fish, root vegetables, whole grain bread and oatmeal, apples, pears, cabbage). Those who most closely followed a Mediterranean diet were significantly less likely to die during the study period than those not following a Mediterranean diet. Similarly, each 1-point increase on the Modified Mediterranean Diet Score or the Healthy Nordic Food Index was linked with improved survival.
Journal of Nutrition. 2017 Apr;147(4):636-644. (Ratjen I et al.)

Childhood obesity is a growing problem around the world, and in developed countries, it is estimated that ⅓ of children are overweight or obese. In a study of 1,032 Greek teenagers (average age = 14), researchers tested a 6-month school-based nutrition education intervention, based on the principles of the Mediterranean Diet. Following the intervention, the researchers found significant decreases in overweight and obesity, abdominal obesity (specifically waist circumference), and blood pressure.
European Journal of Clinical Investigation. 2017 Apr 13. [Epub ahead of print] (Bacopoulou F et al.)

Although fruit has naturally occurring sugars, research continually demonstrates that fruit is an important part of a healthy diet, even for people with diabetes. In a large study of nearly half a million adults in China, researchers found that those eating fresh fruit daily were 12% less likely to develop diabetes over the 7-year study than those who rarely or never ate fresh fruit. Additionally, adults who had diabetes at the beginning of the study were 17% less likely to die over the study period, and were 13-28% less likely to have blood vessel complications.  
PLoS Medicine. 2017 Apr 11;14(4):e1002279. (Du H et al.)

Olive oil is a staple of the Mediterranean diet, an eating pattern praised for its links to good health and wellbeing. To see how olive oil relates to type 2 diabetes, researchers in Europe analyzed data from 4 cohort studies (following people over time and monitoring their health) and 29 clinical trials (randomly assigning people to diets with or without olive oil). They found that those consuming the most olive oil had a 16% lower risk of developing type 2 diabetes than those consuming the least olive oil, with every 2 teaspoon increase in olive oil daily linked with a 9% lower risk. For patients who already had type 2 diabetes, adding olive oil to their diet significantly lowered their HbA1c, an indicator of better blood sugar control.
Nutrition & Diabetes. 2017 Apr 10;7(4):e262. (Schwingshackl L et al.)

Pulses are the food group that comprises beans, peas, chickpeas, and lentils. To see how these foods might be related to diabetes prevention, researchers analyzed data from 3,349 Spanish adults from the PREDIMED trial. Those eating the most pulses (about ⅓ cup per day) were 35% less likely to get type 2 diabetes over the 4-year study period, even after adjusting for overall diet and BMI. Those eating the most lentils (about 1 ½ tablespoons per day) were 33% less likely to get type 2 diabetes, but the relationship was not significant for other types of pulses. Researchers found that by replacing just a half serving of whole grain bread, white bread, rice, or baked potatoes with a half serving of pulses was linked with a 44%, 47%, 52%, and 51% lower risk of diabetes, respectively.
Clinical Nutrition. 2017 Mar 24. pii: S0261-5614(17)30106-1. (Becerra-Tomas N et al.)

In the UK, moderate alcohol intake is defined by up to 3 drinks per day for men and up to two drinks per day for women. To see how drinking alcohol relates to heart disease risk, British researchers analyzed the drinking habits and health outcomes of nearly 2 million adults (although they did not differentiate between beer, wine, and other alcoholic beverages). They found that, compared to moderate drinking, both nondrinkers and heavy drinkers (exceeding the guidelines described above) were significantly more likely to suffer from heart failure, stroke, and death from heart disease, among other (but not all) heart problems. The scientists caution that “there are safer and more effective ways of reducing cardiovascular risk,” than taking up drinking (such as diet, exercise, and quitting smoking), and suggest that “a more nuanced approach to the role of alcohol in prevention of cardiovascular disease is necessary.”
BMJ. 2017 Mar 22;356:j909. (Bell S et al.)

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.)