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Stop Working Out on an Empty Stomach. You're Missing Out on Big Muscle Gains

Working out on an empty stomach doesn't boost your metabolism, and it might negatively affect your health.

Woman preparing fruit smoothie before working out.
JGI/Jamie Grill/Getty Images

Every workout comes with a list of do's and don'ts. Don't wear open-toed shoes, do stretches before your workout, and if it's not already on your list, don't work out on an empty stomach. As you've heard before, food is fuel. Nutritional sustenance gives you the energy to perform physical activities and helps promote a healthy body and mind. While you can work out without eating beforehand, there are a few good reasons you don't want to. 

While eating a large meal before a workout can cause cramping and discomfort, healthy carbs, fats and other nutrients are beneficial. 

Let's explore the importance of a preworkout bite and the consequences of fasted exercise. For more nutritional advice, here are eight foods to help build muscle and four benefits of apple cider you might not know.  

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Worsened performance 

A car can't run without gas. Without sustenance before a workout, you won't perform at your highest potential, nor will your stamina last as long. As you train, your body turns glycogen (a stored form of sugar) into glucose, which promotes better muscle tightening, shortening and lengthening. However, you deplete glycogen levels after a moderate to intense 90-minute workout. To prevent a deficiency in glycogen, experts recommend eating carbs, which have been shown to help improve workout performance and increase intensity. 


When you don't give your body the nutrients it needs to perform properly, it can lead to a significant or sudden drop in your blood sugar. As a result, you're left feeling faint, dizzy and nauseous, which is dangerous if you lift heavy weights or travel long distances during your workout. 

You may burn carbs slower 

In a small-scale study, 12 healthy men ate a breakfast of porridge and milk and then worked out two hours later to determine blood sugar levels and glycogen. The results showed that the men burned more calories during exercise after having breakfast in the morning, and it also helped boost metabolism. It's important to note that the results of this study only considered short-term results. More research is needed to assess the long-term impact and potential benefits that eating before exercising can have on your health.

Researchers suspect the faster clearance of blood sugar was because the body was burning carbohydrates stored in the muscle as glycogen. 

Close up of muscles while working out
milanvirijevic/Getty Images

You miss out on big muscle gains

Protein is a vital nutrient for muscle growth. A small study found that consuming 25 grams of whey protein before a workout increased muscle growth. Skipping out on vital nutrients like protein before a workout means you don't see the muscle gains you could've potentially earned.  

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.