Does Eating Every Three Hours Really Raise Metabolism?

It's a well-established "rule" that frequent meals boost your metabolism and prompt weight loss, but research doesn't necessarily back this rule up. While this eating pattern helps some people, it isn't absolutely necessary for healthy weight management. Eating frequently can help you manage your hunger so you make good choices and avoid bingeing on high-calorie foods. But having a small meal every three hours is no guarantee you'll experience a metabolic boost.

Eating frequently can help you manage your hunger. (Image: Daniel Kulinski/Moment/Getty Images)

The Purported Benefits of Frequent Meals

Many diet plans recommend you eat a meal every three hours to help manage your weight. The theory is, at least from a psychological perspective, eating every few hours helps control cravings and feelings of deprivation when you're trying to lose weight -- you know your next meal isn't too far away. Physically, when you have a small meal every three hours, you feel more satisfied. A 2001 study published in the British Medical Journal concluded that people who ate more frequently tended to be thinner and boast lower levels of cholesterol and blood triglycerides levels than those who ate less frequently.

Several Small Meals Don't Raise Your Metabolism

Proponents of eating every three hours also claim that it boosts your metabolism. About 10 percent of your total metabolic rate comes from the action of digestion. If you eat more frequently, the logic goes, then you digest food more frequently -- raising this part of your metabolism.

No proof that it notably raises your metabolism exists, however. A study published in 2010 in the British Journal of Nutrition compared weight loss in two groups of people who had similar calorie restriction, but one group ate three meals per day; the other split the calories over three meals and three snacks. Both groups lost weight, but the frequent eaters did not lose remarkably more. Another study from 2012 in the journal PLoS One found that a low meal frequency actually helped reduce glucose levels and increased, rather than decreased, resting metabolic rate and appetite.

Possible Pitfalls of Eating Every Three Hours

Regular meals eaten every three hours that are portion-controlled and consist of a balance of lean protein, vegetables, whole grains, unsaturated fat and fruit can support a weight-loss plan. If you've got the time to prepare specific meals and a schedule that permits regularly eating every three hours, you may find this eating pattern helps you achieve your goals. However, failing to monitor portion sizes and the nutrient contents of the meals makes it easy to take in far too many calories when you eat every three hours. France Bellisle, a professor of eating behavior in Paris, wrote in the Scandinavian Journal of Nutrition in 2004 that obese people tend to eat more fat and calories when they eat frequently, for example.

A plan that has you eat every three hours may also override your natural hunger cues. Instead of learning to sense when you really need a meal, you reach for food simply because the clock says it's time. Sticking to a strict eating schedule isn't guaranteed to deliver dieting benefits either. A 2011 study published in Obesity found that frequent eating while on a reduced-calorie diet did not influence feelings of hunger, deter cravings or impart greater sensations of fullness.

Lose Weight With Exercise and Smart Meal Choices

Weight loss occurs when you eat fewer calories than you burn. A deficit of 500 to 1,000 calories per day yields a healthy 1- to 2-pound loss per week. You can spread the calories you do eat across as many meals as you choose -- two, three or six. You have to find a pattern that works for you. Meals that consist of whole grains, vegetables, lean protein, fruits and low-fat dairy support weight loss, good nutrition and satiation.

A true boost to your metabolism happens when you increase the amount of lean muscle you have on your body and exercise more. As compared to fat, muscle mass requires more calories to maintain. By lifting weights and changing the proportion of fat to lean muscle on your body, you'll boost your metabolic rate. Movement burns calories, so formal exercise such as pedaling an elliptical machine, as well as non-exercise activity, such as washing the car and scrubbing the floor, helps increase your metabolism.