Ten Common Nutrition-Related Misperceptions

By: Dan Benardot, PhD, DHC, RD, LD, FACSM

Visiting Professor, Center for the Study of Human Health

The focus on nutrition to attain or maintain a state of good health is an increasingly important feature of the scientific literature. This focus evolves around many nutritionally related factors, including the optimal intake of nutrients (both over time and in real time), the best strategies for reducing obesity risk or returning to a lower bodyfat state, and the optimal distribution of energy substrates (carbohydrates, proteins, and fats) to achieve a state of good health. A common resistance many have in accepting the science is that there are many nutrition myths that make it difficult for people to do the right thing.  Listed below are 10 common nutritionally-related misperceptions that should be considered when determining the best health-promoting nutrition strategy.

• Misperception: Weight is a good indicator of health and well-being
  • Reality: Weight is the wrong measure for virtually everything that it is commonly used for. It’s all about fat mass vs. fat-free (i.e., lean) mass. Make sure that the strategy followed lowers fat-mass while sustaining lean mass, as a reduction in lean mass makes it far more difficult to ‘burn’ energy, commonly resulting in a rebound of higher fat-mass and greater obesity.
• Misperception: The energy cost of exercise is always the same.
  • Reality: Humans are always finding ways to become more energy efficient. Exercise more and we eventually find a way to burn less energy to do this exercise. In humans, energy (kcal) is precious. Therefore, doing the same exercise results in lower energy expenditure, and it feels easier to do. When exercising, try to sustain the same relative exercise intensity so it never feels too easy.
• Misperception: Only eating too much will make you fat.
  • Reality: Humans are amazingly effective fat manufacturing machines. Eat too much food, you make fat. Eat too little food, you lose muscle and make fat. Ideally, there should be a dynamic relationship between energy expended and energy consumed in real time, so you never allow yourself to get too hungry, and you never eat too much at once.
• Misperception: Low calorie diets are an effective weight loss strategy
  • Reality: Low calorie diets are doomed to fail. Adaptive thermogenesis (an adaptation to the lowered energy intake that results in an even lower energy metabolism than the lower caloric intake would predict) leads to same weight on lower energy intake, but the resultant weight has higher fat mass that makes you look bigger and increases cardiometabolic risks.

• Misperception: Supplements are an effective means of improving nutritional status.
  • Reality: Very high doses of nutrients at once (think ‘supplements’) often lead to lower tissue sensitivity and greater risk of toxicity. There is also a higher risk that competing nutrients won’t get adequately absorbed (i.e., too much calcium at once makes it difficult to absorb iron, magnesium, and zinc, etc.). More than enough is not better than enough. Ideally, the vitamins and minerals you receive should come from a wide distribution of foods that are well-distributed throughout the day.
• Misperception: Focusing on ’perfect foods’ assures good nutritional status
  • Reality: People who continuously eat the same few foods because they believe these foods are ‘healthy’ are at risk of malnutrition. They increase the risk of getting too much of something the food that may be ‘bad’, and decrease the chance that they will expose the tissues with all the nutrients they need. There is no perfect food, so always try to eat a variety of relatively low-fat foods that emphasize fresh fruits, fresh vegetables.
• Misperception: Only high sugar intake results in high insulin production, which will make you fat.
  • Reality:There are many ways to increase insulin and make more fat besides eating refined carbohydrates (i.e., sugar), including letting yourself get really hungry and/or eating large meals. Sugar, particularly if provided as liquids when not exercising, does cause problems. However, it shouldn’t be the sole focus of what and how you eat.
• Misperception: Low calorie diets help you lose body fat.
  • Reality: The body’s reaction to an inadequate energy intake is to lower the tissue that needs energy: Lean Mass (…not fat mass). This is a perfectly logical adaptation as the body tries to ‘survive’ an energy intake below that which is required.
• Misperception: 3,500 Calories equal 1 pound of body tissue.
  • Reality: In humans, 3,500 Calories does NOT = 1 pound. Never has, and never will. Humans have adaptive mechanisms that Bomb Calorimeters do not have. Diets commonly reduce energy intake by 500 Calories/day and say that at the end of a week you will have accrued a negative 3,500 Calories and lost 1 pound. Not true.
• Misperception: If you eat (calories IN) the same calories you expend (calories OUT) over a day, weight stays the same.
  • Reality: The commonly stated “Calories-IN, Calories-OUT” paradigm does not work as typically applied in 24-hour units. Humans have an endocrine system that reacts in ‘real time’. So, if you expend 2,500 Calories in a day, and eat 2,500 Calories in a day, the idea that this will keep you healthy and your weight the same is wrong.  In fact, the calories should dynamically match expenditure in a way that satisfies real-time need and helps to sustain normal blood sugar (which in an average person having normal daily activity goes from normal to low in about 3 hours.)

Dr. Dan Benardot is is a Registered and Licensed Dietitian/Nutritionist, and is a Fellow of the American College of Sports Medicine. He recently retired as Professor of Nutrition, and Professor of Kinesiology and Health at Georgia State University, where he served as Director of the Laboratory for Elite Athlete Performance. He is now Professor Emeritus at Georgia State University, and Visiting Professor in the Center for the Study of Human Health at Emory University. Dr. Benardot is the inventor of NutriTiming® web-based and Apple iOS software, which provides real-time actionable advice on energy balance to improve body composition and athletic performance and is the author of several books.