Exercising On An Empty Stomach-- Beneficial??
Posted By: Dr. Gary Bellman on August 29, 2014
It’s a debate that’s sparked controversy since the first weight was lifted: Is it better or worse to work out on an empty stomach?
Different people work out best under different circumstances, and deciding whether someone should eat before a workout can be like telling them what time of day to work out or which diet they should follow; Thus, it largely depends on what works best for the individual.
Contrary to popular belief, research suggests that eating many small meals throughout the day won’t speed up the metabolism, skipping a meal won’t make you fat, and exercising on an empty stomach will not nullify a workout. In fact, skipping a meal or two, also known as “intermittent fasting” (IF), can be beneficial.
An empty stomach triggers a cascade of hormonal changes throughout the body that are conducive to both building muscle and burning fat.
The fasted state produces two significant effects:
1. Improved insulin sensitivity. Put very simply, the body releases insulin (a hormone) when we eat to help us absorb the nutrients from our food. The hormone then takes the sugars out of our bloodstream and directs them to the liver, muscles, and fat cells to be used as energy later on. The trouble is that eating too much and too often can make us more resistant to insulin’s effects, and while poor insulin sensitivity ups the risk of heart disease and cancer, it also makes it harder to lose body fat. Eating less frequently (i.e. fasting more regularly) is one way to help remedy the issue, because it results in the body releasing insulin less often, so we become more sensitive to it—and that makes it easier to lose fat, improves blood flow to muscles, and even curbs the impact of an unhealthy diet.
2. The second reason a good old-fashioned fast can promote muscle gain and fat loss comes down to growth hormone (GH), a magical elixir of a hormone that is said to help the body make new muscle tissue, burn fat, and improve bone quality, physical function, and longevity. Along with regular weight training and proper sleep, fasting is one of the best ways to increase the body’s GH. The effect ends when the fast does, which is a compelling reason to fast regularly in order to keep muscle-friendly hormones at their highest levels.
We can’t speak of muscle-friendly hormones without bringing up testosterone. Testosterone helps increase muscle mass and reduce body fat while also improving energy levels, boosting libido, and even combating depression and heart problems—in both men and women. Fasting alone may not have any effect on testosterone, but there is a surprisingly simple way to produce large amounts of both “T” and growth hormone at the same time, creating an optimal environment for building muscle and torching fat: Exercising while fasted.
In short, fasted training helps to ensure that carbs, protein, and fats go to the right places in the body and are stored only minimally as body fat. Exercising on an empty stomach has been shown to be especially great for fat loss, and it’s even been shown that people who train while fasted become progressively better at burning fat at higher levels of intensity (possibly because of an increase in fat-oxidizing enzymes).
Now, we would be remiss if we didn’t acknowledge that some studies have shown impaired performance as a result of fasted exercise. That said, many of these studies are of Ramadan fasts, which don’t allow the consumption of fluids (which is not advisable when engaging in athletic activities). Still, the prevalence of people who do eat before exercise is pretty good evidence that exercising after eating can work.
There are even studies showing that eating before exercise can lead to fewer calories consumed throughout the day, but that doesn’t discredit the evidence that fasted workouts, even if occasional, can reap a lot of benefits.
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