During the summer months, your skin can synthesize vitamin D from sunshine. That’s fortunate since there aren’t a lot of options for meeting your needs with whole foods. Summertime also has a tendency to increase your awareness about body weight, and a study published in the European Journal of Clinical Nutrition suggests there’s a link between vitamin D status and weight management.

Spanish scientists measured vitamin D levels in 1,266 subjects between 1996 and 1998, 2002 and 2004 and again from 2005 to 2007. About 35% were considered deficient, and those who had lower levels on the second visit were much more likely to become obese over the next 4-year period.

True Strength Moment: Researchers believe that vitamin D plays a role in regulating the function of fat tissue. It’s also important to bone health, and a study outlined on ABB’s Performance Blog suggests timing vitamin D supplementation can impact how your bones adapt to exercise. VisitABBperformance.com to read the story.

Many popular weight reduction diets recommend reducing carbohydrate consumption. Bodybuilders interested in gaining weight typically consume more protein as a percentage of total calories to build muscle mass, but a high-protein diet has also been shown to preserve muscle tissue during periods of caloric restriction. What’s the right balance? A study published in the journal Psychology & Behavior compares 4 different diet strategies.

After 3 months on a diet that restricted caloric consumption by about 60%, 132 middle-aged subjects were put on either a normal protein/normal carb, normal protein/low carb, high protein/normal carb or high protein/low carb diet for 9 months. During this period, calories were restricted by about 30% of the recommended daily amount.

Subjects lost between 24 and 31 pounds on the high-protein diets while those consuming the normal amount of protein only lost 22 to 26 pounds. So consuming a high-protein diet produced more dramatic weight loss regardless of whether carbohydrates were consumed at a normal or reduced level.

True Strength Moment: For this study, a high amount of protein was considered 1 gram of protein per kilogram of body weight. A normal amount was 0.7 grams per kilogram of body weight. For a 200 pound subject, the daily protein target would be about 90 grams on a high-protein diet. A normal amount of protein for the same person would be 63 grams. This would include protein from food as well as supplemental sources.

What’s it take for healthy overweight inactive men to get into shape? Not much, according to research from the Norwegian University of Science and Technology. A 10-week study with a group of 13 subjects showed a 10% increase in maximal oxygen uptake could be achieved with just 4 minutes of intense exercise at 90% of maximal heart rate performed 3 times each week.

Some of these subjects undertook a 4×4 training protocol involving 4 minutes of high intensity exercise at 90% of max heart rate followed by 3 minutes of active recovery at 70% max heart rate. Completing 4 intervals 3 times a week increased maximal oxygen consumption – an established measurement of fitness – by 13%.

True Strength Moment: Despite the promise of fast, easy gains with 12 minutes of training each week, the subjects who worked the slightly more difficult 4×4 program realized better results. These training programs are fine for people with little to no experience working out, but probably aren’t adequate for those dedicated to an active lifestyle.