American Council on Exercise by American Council on Exercise

In a society that is becoming increasingly health conscious, more and more information is constantly coming out on how to lose weight, how to get fit, how to eat, sleep, breathe—everything under the sun that will help you get healthy! It’s a wonder that before this information was available people were able to survive—let alone live healthy lives!

The fact is, people did survive, and were—and are—still healthy without all the weird, scientifically suspect practices that people get tricked into. Nutrition is one of those fields that is inundated with quacks who will try to sell you the latest secret to weight loss. A basic myth-spotting motto: If it sounds too good to be true—it is.

Don’t Be Tricked

Here are some common diet myths that people futily follow in hopes of losing a few pounds.

  • Eating late at night will cause you to gain weight
    Eating late at night, or at any particular time of day, will not cause you to put on more weight than what is normal for what you ate and the activity you did. Weight gain occurs when you consume more calories than you expend, whether that occurs in the middle of the day, the morning or at night. However, in reality, people who eat a lot of food late at night tend to consume more calorie-dense foods and thus eat more calories—which can cause weight gain.
  • You should eat each food group separately for optimal digestion
    Your digestive system is made to handle more than one type of food at a time. It is true that carbohydrate, protein and fat are all digested by different mechanisms, but they can all work simultaneously. Keep in mind that few foods are purely carbs, purely protein or purely fat—so it doesn’t make sense that you can’t mix them.
  • Low-carb/high-protein/no-fat diets are optimal for weight reduction
    A type of diet consistently shown to cause weight loss is a low-fat diet. The key is that you have to eat fewer calories to lose weight, and fat has the most calories per gram, so it’s easiest to cut calories by trimming the fat. The Dietary Guidelines for Americans recommend 20 to 35% of dietary calories come from fat, 10 to 35% from protein, and 45 to 65% from carbohydrate. All of these macronutrients, as well as micronutrients (vitamins and minerals) are essential in the proper amounts for optimal health.
  • Carbohydrates are bad for your health and cause weight gain, and therefore should be avoided
    As far as weight loss goes, the proportion of macronutrients—carbs, fat and protein—consumed is not as important as the total caloric intake versus caloric expenditure. However, foods rich in fiber and protein tend to be the most filling, which in theory would lead to a reduced intake of food and calories compared to high-fat foods and low-fiber carbohydrates. From a heart-health perspective, the healthiest overall meal plan appears to be a Mediterranean-type eating plan, which is rich in fruits, vegetables, whole grains and omega-3 fatty acids from fish, and low in saturated fat, trans fat, sodium and added sugars.
  • Skipping meals is a good way to lose weight
    In theory, skipping one meal while keeping everything else in your diet the same will help you lose weight. But when you skip a meal, your eating pattern changes and you tend to overeat and overcompensate later—which will likely lead to weight gain.
  • The number of meals eaten each day
    Three square meals or five or six small meals—has a huge impact on weight management—Because weight control is achieved by balancing the number of calories consumed with the number burned, it doesn’t really matter if the calories come in the form of three large meals or five or six smaller ones. However, some people find that they’re better able to control their intake one way or the other. In the end, it’s a matter of preference.
  • Grapefruit will speed up your metabolism
    We’ve all heard of the grapefruit diet, the lemon juice diet and a number of other diets that focus on the “secret ingredient” or “magical compound” found in certain foods. Unfortunately, there is no magic bullet to weight loss. There is no food that will help you burn more calories. The only surefire way to speed up your metabolism is to exercise and build muscle.
  • Rapid weight loss can be maintained
    There are many diets out there that promise rapid weight loss, even 10 to 20 pounds in a week. This amount of weight loss is possible on extremely restrictive diets, but it can’t be maintained. A large portion of the weight lost on these types of diets is water and lean tissue, so the minute you get off the diet and go back to eating normally, you’ll gain the weight back—and probably more.
  • You have to stop eating your favorite foods to lose weight
    The most successful approach to weight loss and weight-loss maintenance is to make permanent lifestyle changes that include a healthful eating plan and ample physical activity. A “diet” is not the answer. A healthy lifestyle allows for all foods in moderation.

The Truth

Losing weight and achieving health-related goals requires effort and commitment. Lifestyle behavior changes are typically required to maintain weight loss. Anything above a weight loss of 1 to 2 pounds per week is difficult to maintain. For healthy weight loss, follow these science-based tips:

  • Follow the Dietary Guidelines for Americans. These are summarized at, which provides tools to help you plan and track your diet and physical activity.
  • Get moving! Increase your physical activity with an exercise program, or do simple things like take the stairs, park farther from your destination or walk to do your errands.
  • Surround yourself with support. Encouragement from friends and family is essential when you find yourself unmotivated. If you know someone with similar goals, make him or her your diet/workout buddy and keep each other accountable.  
Additional Resources

ACE Fit Fact: Successful Weight Control
American Dietetic Association—Weight Management Nutrition Fact Sheet
ACE Lifestyle & Weight Management Coach Manual, 2nd ed., Appendix C: Frequently Asked Questions

Preview the PDF

CPR/AED Smart Certification App

Get CPR Certified Anywhere,
Anytime in Just 90 Minutes or Less