Late-breaking study reveals how to NOT pay dearly for dietary indiscretions, slim down, and improve your insulin sensitivity. The trick? Just do your workout at this time of day….
A new study suggests that exercising in the morning, before eating, can significantly lessen the ill effects of a poor holiday diet.
Researchers recruited healthy, active young men and fed them a bad diet for six weeks. A group of them that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. What’s more, they burned the fat they were taking in more efficiently.
According to Drs. Van Proeyen and Szlufcik, the lead researchers at the Dept. of Biomedical Kinesiology, Leuven, Belgium, “Training in the fasted state improves glucose tolerance during fat-rich diet. Plus, working out before breakfast directly combated the two most detrimental effects of eating a high-fat, high-calorie diet. It also helped the men avoid gaining weight.”
A fat-rich energy-dense diet is an important cause of insulin resistance. Stimulation of fat turnover in muscle cells during dietary fat challenge may contribute to maintenance of insulin sensitivity. Exercise in the fasted state markedly stimulates energy provision via fat oxidation. Therefore, researchers investigated whether exercise training in the fasted state is more potent than exercise in the fed state to rescue whole-body glucose tolerance and insulin sensitivity during a period of hyper-caloric fat-rich diet.
The study in question lasted for six weeks. It included 28 healthy men between the ages of 18 and 25, divided into three groups; those who:
- Exercised before eating a carbohydrate-rich breakfast, and drank only water during exercise
- Ate a carbohydrate-rich breakfast before exercising, and drank sugary drinks such as sports drinks during their workout
- Ate an identical diet but did not exercise at all
The men who exercised ran and cycled at a strenuous intensity four times a week.
Overall, the men had identical high-calorie, high-fat diets. The primary difference was whether — and most importantly, when — they exercised. The other difference was the type of beverages they drank during exercise.
At the end of the trial, the non-exercising control group had gained an average of more than six pounds, and had developed insulin resistance — the precursor to Type 2 diabetes.
Those who ate breakfast prior to hitting the gym gained an average of about three pounds; half the weight gain of those who did not exercise. However, they too had developed insulin resistance.
The only group that gained almost no weight, and showed no signs of insulin resistance were those who exercised before eating breakfast, and drank only water during their workout.
The type of beverage consumed during exercise can also have a major impact on your weight loss and health goals. You should avoid all types of sugary drinks, including sports drinks, for up to two hours after your workout because fructose obliterates the growth hormone response.
Clearly, the fasting exercise group reaped the benefits of both fasting and not ruining their efforts with carbohydrate-rich beverages.
The authors concluded that: “This study for the first time shows that fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet.”
The results were remarkable, considering all three groups consumed very high caloric diets. This is powerful evidence that occasional indulgences do not have to lead to excessive weight gain.
This study for the first time shows that fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet. From the results, it becomes very clear that something as simple as modifying your schedule to exercise before eating your first meal of the day can have a very beneficial and protective impact on your health and weight.
Journal of Physiology Nov 1, 2010;588(Pt 21):4289-302; Van Proeyen K, Szlufcik K., Nielens H.