If you don't eat, you might feel slow-moving or lightheaded when you exercise. If you plan to exercise within an hour after breakfast, eat a light meal. Or have a sports drink. Focus on carbohydrates for the most energy.
No, it is not recommended to work out if you don't have food. Working out on an empty stomach can lead to low energy, headaches, nausea, and poor performance.
Exercising in a fasted state may burn some quick body fat, but it's not the best option for your body in the long-run. Eat a small snack or meal before and after your workout to ensure that you're properly fueled to perform your best in the gym and recover quickly when you get home.
Yes, more fat calories can be burned by exercising on an empty stomach, the total amount of calories burned is equal to the same workout after eating a light breakfast.
Working out on an empty stomach won't hurt you—and it may actually help, depending on your goal. But first, the downsides. Exercising before eating comes with the risk of “bonking”—the actual sports term for feeling lethargic or light-headed due to low blood sugar.
Overtraining and undereating can not only cause you to lose efficiency, but it can also cause you to lose muscle mass. If you have weight loss goals, eating less may sound like a good idea, but if it doesn't align with your fitness goals, you won't see the results you're hoping for.
When you exercise in a fasted state — after a night's sleep and before you eat breakfast — then you do actually use more fat as a fuel source during exercise. But research from my team has shown that performing exercise in a fasted or fed state does not have any meaningful impact on body fat in the medium to long term.
That plan is called the 30-30-30 rule. It's a simple but catchy idea that encourages you to eat 30 grams of protein within 30 minutes of waking up and then get 30 minutes of low-intensity exercise. The 30-30-30 rule now has millions of followers on TikTok.
In other words, fasted cardio may burn more fat during exercising, but that effect is counterbalanced by an increased carbohydrate burn later in the day. On the other hand, research shows that subjects who ate before exercising oxidized more fat in the recovery period than those who performed fasted cardio.
Overall, the experts agree: Exercising in the morning is the best time of day to work out for logistical, effective and health reasons. When it comes to weight loss, a 2023 study published in the journal Obesity found exercising between 7 a.m. and 9 a.m. could help.
Think about your fitness goals. For example, if your goal is to boost your metabolism and start the day energized, morning workouts may be more suitable. If your aim is to improve performance and relax after a stressful day, evening workouts might be better. Consider your temperature preferences.
So, running on an empty stomach helps our muscles use fat for fuel. This habit is great for burning more fat. By exercising without blood sugar, our body learns to use stored fat. This allows us to run longer and perform better, thanks to the energy from fat.
Fasted cardio involves working out on an empty stomach, typically first thing in the morning. Some experts and fitness enthusiasts claim that this allows you to burn more fat and calories than working out after you've eaten. Currently, there is not enough scientific evidence to support these claims.
If it's an easy-going, 30-minute session, you may be able to get away with skipping a pre-workout snack. “But if you're going for an hour or more, you really should get something to eat,” says Patton. Working out on an empty stomach also could cost you what you're trying to build — namely, muscle.
“Eating right before bed requires your body to do an awake function, which disrupts your circadian rhythm.” And eating late at night doesn't just affect your sleep. According to Barclay, it can also cause you to overeat, or even cause gastrointestinal discomfort.
Studies suggest that eating or drinking carbohydrates before exercise can help you do better during your workout. And the carbohydrates may allow you to work out for a longer time or at a higher intensity. If you don't eat, you might feel slow-moving or lightheaded when you exercise.
You can get away with not eating before an exercise session if it is low-intensity or less than an hour. If you haven't eaten for a few hours beforehand, it's important to have a balanced meal soon after (within an hour) to recover and refuel.
When it comes to nutrition advice via social media, trust me, I've heard worse. The 30-30-30 method refers to consuming 30 grams of protein within 30 minutes of waking, followed by 30 minutes of low-intensity exercise. Biologist Gary Brecka describes the diet on TikTok, which now has more than 17 million views.
4-Hour Body Diet: Health Risks
Restricting entire food groups could lead to deficiencies in certain vitamins and other nutrients, including vitamin D and calcium (found in dairy) and B vitamins such as folic acid (found in grains and fruit).
The recommended dietary allowance to prevent deficiency for an average sedentary adult is 0.8 grams per kilogram of body weight. For example, a person who weighs 165 pounds, or 75 kilograms, should consume 60 grams of protein per day. If you're over age 40-50.
Hunger alone cannot exactly burn fat. Just being hungry does not mean your body is burning fat. The body uses sugar for energy in case of hunger and not the fat reserve. It might play a small role, though.
According to Gam, you can—and should—do light cardio, like walking, every day; however, engaging in moderate-to-high intensity cardio seven days a week is not advised. “I would recommend everyone, even the fittest athletes, be taking at least one rest day per week for recovery,” says Gam.