How Food Affects Your Muscle-Building Hormones

Want to build muscle faster? Understand how what and when you eat affects hormonal responses in your body.

You've heard the phrase "you are what you eat," right? More accurately, you are how your body responds to what you eat. What you put in your mouth can have a dramatic effect on your hormones—the all-important chemicals that tell your body what to do.

When it comes to building performance-fueling muscle, knowing how your body responds to carbohydrates, fats and proteins will help you get bigger, faster. Here's how each of those nutrients can affect your hormones, and how much you should eat of them to build the muscle you want.

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Your body's growth hormone levels play a significant role in—you guessed it—muscle growth. Growth hormone levels increase significantly when insulin levels are low. Levels of testosterone, the hormone responsible for things like strong bones, muscle growth and protein synthesis, also increase when insulin is low. So obviously, if you're looking to build muscle, it's to your benefit to keep your insulin levels in check.

You can control the levels of insulin in your blood by monitoring the kinds of carbs you eat. Complex carbs do not spike your blood sugar and the resulting insulin response as much as simple carbs do, because complex carbs are released into the bloodstream at a slower rate.

A full 50 to 60 percent of your daily calories should come from carbohydrates (studies have shown that growth hormone actually fails to cause growth if you restrict carbs from your diet), and 45 percent of them should be complex carbs. Throughout the day, you should munch on complex carbohydrates like oats, potatoes and beans. Skip the simple carbs unless you are within the four-hour window following your workout. During that time period, consume simple carbs like white rice, thoroughly cooked pasta and fruits, at a rate roughly 1.2 grams per kilogram (approximately .54 grams per pound) of body weight.

Focusing on complex carbohydrates will keep your insulin levels low, which will keep your testosterone and IGF-1 levels high.

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Protein intake is also positively correlated with levels of growth hormone and IGF-1 in the body. These hormones, collectively, exert an anabolic (muscle-building) effect.

Although research has shown that a diet high in protein lowers total testosterone levels compared to a high-carb diet, protein also lowers sex-hormone-binding globulin (SHBG) in the body. As a result, eating protein actually frees up more testosterone. A 2001 study that looked at the relationship of protein intake to SHBG found that the higher your protein intake, the lower your levels of SHBG. The lower your levels of SHBG, the higher your levels of testosterone.

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Strike a balance between protein and carb consumption—approximately 1.5 to 2 grams of carbs to one gram of protein is ideal—to ensure that SHBG and testosterone are balanced. Keeping your protein intake between 25 to 35 percent of your daily calories will prime your testosterone and growth hormone levels for muscle growth. 


Studies have shown a positive correlation between fat consumption and testosterone. For example, a 2005 study of 39 middle-aged healthy white men (ranging from 50 to 60 years old) asked them to switch from their native diet (which was high in fat and low in fiber) to a low-fat, high-fiber diet for eight weeks. The result of the dietary change was a reduction in total testosterone production.

Penn State researchers showed that the effect of dietary fat on testosterone levels depends on the kind of fat consumed. Specifically, they found that monounsaturated and saturated fat raise testosterone levels. A 2009 study out of Argentina showed that olive oil (monounsaturated) and coconut oil (saturated fat) increase the activity of the 3beta-HSD and 17beta-HSD enzymes, which are involved in the production of testosterone.

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Half of your fat intake should come from saturated fats, like animal fat and tropical oilsAnother quarter should be the essential fatty acids, and the remaining quarter should be monounsaturatedAim to consume between 20 and 30 percent of your daily calories from fat.

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What All This Means For You

The above information won't do much for you if you cannot apply it in your diet. To figure out how you should do that, consider the findings of a 2011 study.

In the study, rats were fed a 4-gram trial meal, after which muscle protein synthesis peaked at 90 minutes, then returned to normal after 180. Rats later consumed another a 4-gram meal, except this one was comprised of 20 percent whey protein. The rats were given either 2.63 grams of carbs, 270 mg of leucine (an amino acid), both, or water 135 minutes after that.

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Rats administered leucine and/or carb supplements at 135 minutes post-meal maintained peak muscle protein synthesis through 180 minutes. Basically, the researchers found that by eating every 135 minutes, the rats were more likely to build more muscle. This doesn't mean the results will be the same for humans, but if you want to add beef to your bones, eating more frequently is worth a shot.

Bottom line: To fuel faster muscle growth, make sure your meals and snacks are comprised of 20-30 percent fat, 25-35 percent protein and 50-60 percent carbohydrates—and eat approximately every 2 hours and 15 minutes

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