5 Nutrition Myths Explained

5 Nutrition Myths Explained

Your metabolism is not slow

The term “slow metabolism” gets thrown around a lot. While metabolic rates can differ from person to person (on averages a 100-300 calorie difference) your metabolism is not slow, it’s adaptive. To first understand why your metabolism is adaptive first we need to look at what all goes into metabolism. Metabolism is the sum of all chemical process in your body that keeps you alive. The amount of calories your body burns in a day is called your total daily expenditure (TDEE). Your resting metabolism rate (RMR), non exercise activity thermogenesis (NEAT) , thermic effect of food (TEF), and exercise activity thermogenesis (EAT) all go into determining the amount of calories you will burn in one day. Your RMR is the energy your body uses to keep you alive and is mostly determined by your fat free mass. Basically RMR is the energy it takes to keep all your organs, skeletal muscles, and fat stores functioning. RMR is about 70% of your metabolism. Thermic effect of food (TEF) refers to the energy it takes to digest, absorb, and metabolize the food that you eat. Fat has 9 calories per gram and a 0-3% TEF, carbohydrates have 4 calories per gram and a 5-10% TEF, and protein has 4 calories per gram and a 20-30% TEF. Non exercise activity thermogenesis is exactly what is sounds like, activity outside of exercise. This can be walking, cleaning, etc. This is where the popular 10k steps a day comes from. Walking is a great form of exercise and is also the cheapest form of exercise. Lastly, your exercise activity. Surprisingly, this is the littlest part of your metabolism. Your RMR is the largest, then NEAT, TEF, and then EAT. This is why it is important to be active outside of the gym as well. All of these factors make up your metabolism but they are not set in stone for each person. Meaning the amount of calories I burn is not the same as the amount you are going to burn. Metabolism is very dependent on muscle mass, fat mass, sex, age, genetics, diet, activity, weight, insulin sensitivity, sleep, stress, and past dieting history. All these things can cause your metabolism to adapt. So when we increase activity your metabolism will adapt, when you diet your metabolism will adapt, when you gain weight it will adapt, when you have high amount of stress it will apart, etc. But why? Simply put, to keep you alive. Your body will adapt so it can use less energy to keep you alive. Lets focus on dieting. Dieting is basically controlled starvation. When you diet you eat less and then begin to weigh less. This causes TEF to decrease because you aren’t eating as much, RMR will decrease because you weigh less, same with EAT and TEF. All these process will adapt to keep you alive. If you’re eating 1200 calories (which is the amount a toddler needs not a grown adult, please do not do this) your body will adapt and learn to live off of 1200 calories. Your body does not know that you have access to food it thinks that you are starving and now your body wants to do everything it can to keep you alive by adapting and using less energy. This is why when we diet we want to start on the highest calories possible. Metabolic adaption will occur and if you start on 1200 calories there is no room to decrease but starting at 2200 you have room to decrease once metabolic adaption occurs.

**These calorie numbers are meant for examples

Eating 3 bigger meals does not increase your metabolism-neither does 6 smaller meals

At one point it was said that if you wanted to increase your metabolism you should eat 6 small meals throughout the day. This is not entirely true and it really comes down to understanding the thermic effect of food. As mentioned previously the thermic effect of food (TEF) is the amount of energy your body expends while digesting, absorbing, and metabolizing food. Someone eating 1800 calories per day will burn about 180 calories from TEF. If that person ate six 300 calorie meals that is 30 calories from TEF six times totaling 180 calories at the end of the day. Eating three 600 calorie meals would equal 60 calories from TEF three times a day still totals 180 calories a day. While there are ways to increase your metabolism (ex: moving more) eating more or less meals a day has no effect on increasing your metabolism if calories are static.

Carbs are not bad for you

Carbohydrates get a bad rep and it is mostly caused by the role of glycemic index or insulin. The glycemic index of a food does not determine if it is unhealthy or not. Our bodies need carbs. Carbohydrates are primary made up of glucose which provides half of the energy your muscles and tissues use. Your brain needs 130 grams of carbohydrates just to function and its preferred source of energy is glucose. Glucose is converted to the liver and can be used as energy, stored as glycogen in our liver and muscles, or it can be converted to glycerol and fatty acids and stored as fat. The glucose is stored as fat only if the body has enough energy already or if glycogen stores are full. Storing excess carbohydrates as fat is the body’s last choice. Storing carbohydrates as fat is also a very demanding process which is why it is our bodies last choice. Other functions that carbohydrates contribute to are sparing protein and preventing ketosis. By sparing protein adequate carb intake allows the body to use protein for other essential functions. Your body does not store extra protein, like it does glucose, to provide energy so without adequate carbohydrates the body will take protein from your muscles and organs to provide glucose. Many foods that contain carbohydrates also provide fiber which is helpful for digestion. Carbohydrates can contribute to weight gain but not by themselves. You gain weight from an excess of calories.

Fat is not bad for you

Fat just like carbohydrates gets a bad rep. It makes since eat fat get fat right? No not exactly. Just like carbohydrates fat provides the body with energy. Stored triglycerides protect bones, organs, nerves, and help maintain your body temperature. Dietary fat provides essential fatty acids that aid in absorption of fat soluble vitamins. Dietary fat is also important for healthy skin, hair, and hormones-especially in females. So if fat is an essential part of the body how did it get such a bad rep? Well fat provides 9 calories per gram, double the amount carbohydrates and protein provide, therefore it is very calorie dense and easy to over eat. Also fat does not have a ton of options like carbohydrates do. Fat is either used as energy or its stored as fat. It is easier on your body to store excess fat than it is to store excess carbohydrates and proteins. However, just because it is easier to store does not mean it is bad for you. I mentioned a lot of benefits of fats above. Again, fat alone does not contribute to weight can. You gain weight by eating excess calories. These excess calories can come from anything. Lets talk about the saturated fat argument. This is another reason that fat gets a bad rep. It was once said that saturated fats are bad because they cause diseases, such as heart disease. However, new research suggests that saturated fats do not directly cause heart disease. It does not cause heart disease by itself. Just like carbohydrates and fat do not contribute to weight gain by themselves. Instead of focusing on one certain thing that can contribute to issues look at the big picture, your overall diet and lifestyle.

Gluten is not bad for you

Gluten is a type of protein that is found in wheat and grain products. Those that have celiac disease or non celiac gluten sensitivity should avoid foods with gluten. There is no evidence that states that gluten is harmful to those who do not have celiac disease or NCGS. It was stated that gluten could cause tissue damage, however there is no evidence to support this. There was however a study that was conducted and found that gluten intake increased weight gain. However, this study was conducted in rats and they were given an extreme amount of gluten. It is unclear how this study would play out in humans. As of right now there is no evidence to support consuming gluten is bad for your health. There is also no benefit to consuming a gluten free diet if you do not have a reason to. Some recent studies have suggested that foods containing gluten could improve blood lipids, control blood pressure, and even boost the immune system. A lot of foods that contain gluten also have fiber, vitamins, and minerals. Foods that are made gluten free are usually low in these nutrients and many are higher in calories. Also they are more expensive.

Take home message

There is not one thing that contributes to issues, it is always a combination. Instead of just focusing on that one thing that is said to cause all the issues focus on the bigger picture. Your overall diet and lifestyle are most important.

Freire RH, Fernandez LR, Silva RB, Coelho BSL, Araujo LPTde. Wheat gluten intake increases weight gain and adiposity associated with reduced thermogenesis and energy expenditure in an animal model of obesity. Int J Obes (Lond) . 2016;40(3). doi:10.1038/ijo.2015.204

Galgani J, Ravussin E. Energy metabolism, fuel selection and body weight regulation. International Journal of Obesity. 2008;32(S7). doi:10.1038/ijo.2008.246

Galgani J, Ravussin E. Energy metabolism, fuel selection and body weight regulation. International Journal of Obesity. 2008;32(S7). doi:10.1038/ijo.2008.246

Lusis AJ. Atherosclerosis. Nature. 2000;407(6801):233-241. doi:10.1038/35025203

Palmer MA, Capra S, Baines SK. Association between eating frequency, weight, and health. Nutrition Reviews. 2009;67(7):379-390. doi:10.1111/j.1753-4887.2009.00204.x

Rosenbaum M, Leibel RL. Adaptive thermogenesis in humans. International Journal of Obesity. 2010;34(S1). doi:10.1038/ijo.2010.184

Stein K. Severely Restricted Diets in the Absence of Medical Necessity . Journal of Academy of Nutrition and Dietetics . 2014;114(7):986-987.