What happens if you work out and don eat

Short-term fasts -- for three days or so -- are safe, but longer-term fasts may not be safe. Fasting also slows your metabolism, making it difficult for you to keep up an exercise routine. If you fast and try to exercise, you risk your body burning muscle tissue instead of fat tissue for fuel. You'll lose weight this way, but you won't be getting rid of your stored fat deposits. During an extended fast, you also risk several serious health effects, such as problems with your heart rhythm, kidney stones, liver damage and anemia.

In addition, people who fast or eat too little and then engage in vigorous exercise may have exercise addiction or an eating disorder. If you want to lose weight through diet and exercise, you can do it -- just tone it down so you're eating enough to provide the energy you need for your workouts. You should consume a balanced diet with plenty of high-quality carbohydrates such as whole grains and fresh produce.

In addition, your workouts should last about three-quarters of an hour almost every day of the week. That way, you can lose weight without starving yourself. SELF does not provide medical advice, diagnosis, or treatment. Any information published on this website or by this brand is not intended as a substitute for medical advice, and you should not take any action before consulting with a healthcare professional.

Skipping post-workout refueling can leave you feeling tired and foggy, and can get in the way of recovery. Go for snacks or meals that have both carbs and protein. After particularly sweaty or long workouts, you might need to replenish electrolytes, too. Never overlook good ol' fashioned hydration. Amy is a freelance writer who covers health, fitness, outdoors, and travel. She holds a B. Read more. Topics electrolytes Post workout exercise nutrition. Sign up for our SELF Motivate newsletter Get exclusive workouts, fitness tips, gear and apparel recommendations, and tons of motivation with our weekly fitness newsletter.

Enter your e-mail address. But sports dietitian Katherine Shone says the information has been twisted and our bodies will actually only break down muscle in a "dire straits situation". If you think of your body like an engine, Shone says there are a number of different "petrol" sources that it'll use. The immediate source is carbohydrates, which are stored as glycogen in the muscles, followed by fatty acids.

If the body has completely exhausted all glycogen and fatty acid stores, then it will turn to breaking down muscles — but that's a very rare event for a healthy gymgoer. Interestingly, the way our bodies use fuel does change depending on the intensity and duration of the exercise session.