Three groups of healthy, physically active men (between the ages of 18 and 25 years) were all fed the same high-fat, high-calorie diet for six weeks. One group, however, exercised before eating a carbohydrate-rich breakfast, and drank only water during exercise. Another group ate a carbohydrate-rich breakfast before exercising, and drank sugary drinks such as sports drinks during their workout. Exercise for these two groups consisted of running and cycling at a high intensity four times a week. A third group did not exercise at all.
It’s not surprising that the group that did not exercise gained weight (an average of six pounds) and developed insulin resistance – a precursor to type II diabetes. More surprising was that the group that the group who ate breakfast prior to hitting the gym (and consumed a sports drink during exercise) gained an average of about three pounds and, like the non-exercisers, developed insulin resistance. By comparison, those who exercised before breakfast (and drank only water) gained almost no weight and showed no signs of insulin resistance.
So what might we conclude from these results? Well, if you want to maximize the metabolic benefits of working out, you may want to exercise before breakfast and, if you are exercising an hour or less, skip the sports drinks. Now if you are a competitive athlete going out for a long ride or run in the morning, of course you’ll want to fuel up before your workout and bring a snack on the road with you. But for those of you hitting the gym before work, if weight loss or maintenance is your goal, you may want to wait to eat until after you’ve exercised and hydrate with water only. Or, consider having a glass of milk before your workout. It’s the original sports drink - and an ideal blend of complex carbohydrates and protein to both fuel and refuel your muscles.