Science and Medicine

“We don’t yet understand exactly what mechanism is causing low-fat chocolate milk to give athletes these advantages—that will take more research.”

Drinking low-fat chocolate milk after a vigorous workout builds muscle, reduces fat, and increases aerobic endurance.

Two related studies compared the recovery benefits of drinking low-fat chocolate milk after exercise to the effects of a carbohydrate beverage with the same ingredients and calories as typical sports drinks as well as to a calorie-free beverage.

“The advantages for the study participants were better body composition in the form of more muscle and less fat, improved times while working out, and overall better physical shape than peers who consumed sports beverages that just contained carbohydrates,” says John Ivy, professor of kinesiology and health education at the University of Texas-Austin.

The research is published in the Journal of Strength and Conditioning Research.

After riding a bike for 90 minutes at moderate intensity, then for 10 minutes of high intensity intervals, 10 trained cyclists had significantly more power and rode faster (reduced their ride time by an average of six minutes) when they consumed low-fat chocolate milk rather than a carbohydrate sports drink or calorie-free beverage.

Compared to other recovery drinks, chocolate milk drinkers had twice the improvement in maximal oxygen uptake after four and a half weeks of cycling, which included intense exercise five days a week, with each exercise session followed by one of the three recovery beverages.

Maximal oxygen uptake is one indicator of an athlete’s aerobic endurance and ability to perform sustained exercise.

Read more: Chocolate Milk Does a Body Good

The researchers note that rats fed the tasty, highly palatable cafeteria diet ate more food—about 30 percent more calories—than those eating high-fat or high-sugar diets.

The typical American diet—filled with processed foods like cookies and chips—may pack on more pounds than a high-fat diet.

Rats fed a snack-based diet of highly palatable, energy-dense foods gained more weight, had more tissue inflammation, and were intolerant to glucose and insulin (warning signs of diabetes) than rats whose diets were high fat from lard. The study is featured on the cover of this month’s issue of the journal Obesity.

“Obesity has reached epidemic levels in the United States,” says Liza Makowski, assistant professor of nutrition at the University of North Carolina at Chapel Hill and the study’s senior author. “These findings provide us with a better animal model to help explore what factors are contributing most to this dangerous trend, and what strategies for prevention and treatment of obesity will be most successful.”

Using obese rats in laboratory experiments has been a common practice for decades, but rodents are typically made obese on manufactured lard-based, high-fat diets, Makowski notes. Her team showed that feeding the rats a diet that more closely resembles a typical American diet filled with snacks—known as the “cafeteria diet,” or CAF—revealed even more severe risks and emphasized the potentially harmful nature of excessive snacking.

Read more: Junk Food Worse than Lard for Weight Gain