Friday, July 07, 2006

Weight Loss: Do You Lose More Weight When Exercising On An Empty Stomach?

Today I would like to talk about when is the best time to exercise for maximum weight loss. While the type of exercise, the intensity and duration is important with respect to weight loss, the time of exercise is equally as important – if not more so.

Timing your workout can be crucial. There are specific times during the day during which your body burns fat most efficiently. It has to do with your eating cycle - or more accurately with your body’s digestive cycle. The body burns more fat when you exercise on a relatively empty stomach – contrary to many claims out there that state otherwise. The longer you wait to exercise after a meal the more fat your body will burn.
Is that truth or myth?

A university researcher studied the effects of exercising on a full versus an empty stomach. A group of women participated in 2 exercise studies. In one they exercised twice before meals and in the other, after meals. Evidence showed that when the subjects exercised on an empty stomach (before meals), blood glucose levels were lower in the periods following meals and during the night, than the when they exercised on a full stomach (after meals).

This suggested that exercising before meals can help to regulate blood glucose levels almost as well as 2 popular glucose-lowering drugs. (1)
To take it one step further, since this type of exercise method lowers blood glucose, lower amounts of glucose may translate to decreases in body fat. Remember excess glucose in the blood (from carbohydrate) may be stored as fat.

This study, it seems, supports the widely popular theory that the best time to exercise for fat loss, is on an empty stomach. A theory which many claim is only a myth.

I decided to put this theory to the test. I am well into my thirties now, and I find it more difficult too keep the pounds off these days (with everything being constant). In other words, I am not eating more calories than I did 10-15 years ago and I’m also not exercising any less. And yet I had put on an extra 12 pounds. By the way, I also have a slow metabolism.

So, I wanted to see if there would be a significant difference when I exercised before breakfast instead of 2-3 hours after dinner which is what I had been doing. My workout was exactly the same, I didn’t change anything. I jogged for 30 minutes and followed that by 15 minutes of high intensity interval training. The results were shocking. I lost 11 pounds in four and a half weeks – that was extra weight around the mid-section that I was carrying around for quite some time.

In truth, however, I am not really a morning person and find that my body has a hard time waking up for a workout first thing in the morning. If you’re not a morning person, you’ll know what I mean. So I am going to experiment by switching my workout period to first just before lunch and then just before dinner (on a fairly empty stomach). I’ll let you know what the results will be. I have a feeling they’ll still be more favorable with respect to weight loss than when workouts are conducted after meals.

Reference:, “Exercise nearly as successful as drugs at lowering blood sugar”, retrieved 6 July 2006 from

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