Appetite can be tricky. Sometimes you feel hungry right after scarfing down a giant meal. Other times, you may go well past noon without desiring a single bite of food. There are many factors that contribute to feelings of hunger, and research shows that exercise is one of them. Working out affects appetite hormones, and thus may reduce your desire for food. However, the extent of this reduction depends on the type of exercise you do, and the effects are short-lived.
Exercise and Appetite
In 2008, researchers at Loughborough University in the United Kingdom looked at exercise and hunger patterns among a sample of students. At different times, the students participated in two activities: running for an hour on a treadmill and lifting weights for an hour and a half. After they ran, participants had lower levels of peptide YY and ghrelin, two hormones that stimulate appetite. After weightlifting, they only had reduced ghrelin. These findings indicate that appetite may drop after working out, especially after cardio. But don't expect your workout to make you eat less all day -- the effects only lasted for about two hours.
If you have lost your desire for food, it may not be due to exercise. If you feel sad, anxious or depressed, these feelings could be to blame. A physical illness, such as a cold or flu, can also decrease your hunger, as can the first stages of pregnancy. In rare cases, serious illnesses like hepatitis, kidney disease and certain cancers are to blame for lack of hunger. If your appetite is sharply reduced for an extended period of time, seek a medical professional pronto.
Starting a Workout
Before jumping headlong into a workout routine, it is important to take some precautionary measures. Starting a heavy routine right off the bat can leave you exhausted and even lead to injury. Start slowly, doing 30 minutes a day of moderate cardio, such as cycling on a flat surface or walking quickly, five days a week. Do strength-training such as squats, pushups and crunches two days a week, working all muscle groups. Slowly ease into more intense activity, like running, and add more time gradually as you become more fit.
Appetite and Nutrition
If you are trying to lose weight, you may consider a reduced appetite a good thing -- and it can be. In order to shed pounds, you need to consume less energy, or calories, than you expend. It is safe to cut calories down to 1,200 a day, but not lower. So if you aren't eating enough to allow for proper nutrition, make an effort to take in an adequate assortment of healthy foods such as produce, lean proteins such as salmon and kidney beans, whole grains such as oatmeal and quinoa, and small amounts of unsaturated fat.
Nina K. is a Los Angeles-based journalist who has been published by USAToday.com, Fitday.com, Healthy Living Magazine, Organic Authority and numerous other print and web publications. She has a philosophy degree from the University of Colorado and a journalism certificate from UCLA.