Calories are our means to survival. This biological unit provides us with the energy needed to perform any activity, from running errands to exercising and even simple indigenous tasks such as waking up, breathing, eating, talking and cognitive thinking. Proper calorie intake keeps our metabolism at optimal levels, thus allowing us to perform better in an exercise setting, a professional setting and a personal setting. In a nut shell, adequate calorie intake gives us the energy needed to thrive on a day-to-day basis. However, there seems to be a misconception on what constitutes adequate calorie intake needed to maximize health and performance. This misconception is not easy to answer since everyone’s body composition, metabolism and activity level are different. Yet, there is one absolute answer that never changes: every individual should consume, at minimum, their Resting Metabolic Rate (RMR) in calories.
RMR is the baseline amount of calories burned every day without exercise that is needed to maintain normal bodily functions, including waking up, breathing, blood circulation, digestion of food, and brain activity. Factors such as body composition (or the distribution of muscle and fat), current activity level and current amount of food intake all play a role in determining an individual’s RMR. RMR is most accurately determined in a lab setting; however, this value can also be estimated based upon your height, weight, age and current activity level. MyPlate.gov is one site that can do this estimation. Generally, women have an RMR of 1,200 calories per day while males have an RMR of 1,500 calories per day. These numbers are based on national averages established from research and can be higher or lower depending on the aforementioned factors (i.e., a higher muscle mass equates to a higher RMR and a lower activity level equates to a lower RMR). When comparing this number to your current calorie intake, it is important to consider that this number does not include physical activity. Physical activity can include anything from exercise to running errands, cleaning the house, walking and anything that requires an individual to move. On average, physical activity can add anywhere from 100-1,000 (or more) calories to the RMR depending on the intensity and duration of the activity, meaning an active female could be burning anywhere from 1,300-2,200 (or more) calories on a given day. With this range in mind, think back to your own calorie consumption and ask yourself, am I eating enough?
Let’s examine the consequences of consistently lower than normal caloric intake. An individual may be in this situation due to dieting or simply not being aware of their healthy range. Regardless of the situation, there are acute and chronic risks associated with this deficit. Low calorie intake in a given day can lead to feeling lethargic, headaches due to the lack of sugar needed to fuel the brain and even feeling faint. If exercise is performed while in this deficit, then all the aforementioned signs would be magnified, and the ability to get the most out of your workout is severely reduced. On the other hand, continuously eating a low amount of calories can cause the body to go into “starvation mode,” which basically means the body will drastically lower the amount of calories it burns every day in order to fuel the vital bodily functions meant to keep us alive. Furthermore, because the body is not receiving a sufficient amount of calories, it must go searching for other sources of energy. The first source of energy the body will use is muscle. Muscle houses mostly glycogen (a complex form of sugar) and protein, both of which contain four calories per gram compared to fat, which contains nine calories per gram. Your body recognizes that fat contains more energy and will conserve as much fat as possible to maintain energy for survival. As a result, muscle is broken down and muscle mass decreases. A decrease in muscle mass leads to a decrease in metabolism, as well as a decrease in body weight, but not in a healthy way. Muscle weighs more than fat per square inch; therefore, the body weight lost from continuous caloric deficit is due to a loss of muscle, meaning body fat percentage remains relatively the same. Another consequence of constant caloric restriction is a decrease in thyroid hormone production. This hormone is responsible for the breakdown of nutrients (carbohydrates, proteins and fats) that are later converted to energy for physical activity. An individual who eats a healthy amount of calories, as well as who is moderately active, usually has a high amount of thyroid production in order to constantly breakdown nutrients and use them for energy. On the other hand, when the body is not receiving enough calories, it must compensate by reducing thyroid production in an effort to conserve energy. This means that instead of effectively breaking down nutrients for energy, the body will be more effective at breaking down nutrients for storage. In a nut shell, constant caloric restriction could lead to a decrease in the amount of calories burned every day, a decrease in muscle mass and an increase in food being stored rather than burned.
The majority of companies that advertise nutrition counseling have the habit of advertising the latest and greatest diet, claiming to produce groundbreaking results. These agencies normally advertise that restricting caloric intake or restricting certain nutrients from your diet will lead to healthy weight loss. Yet, is the satisfaction of losing pounds through prolonged caloric restriction really worth it? There is no one-size-fits-all guide for calorie consumption. If you are looking to adjust your current diet, the best place to start is consulting MyPlate.gov for help on the type and quantity of nutrients to consume that is best for your body. If you want further assistance, contact your physician or a nutritionist to help you make a plan. Food is good and calories are good, so consume a healthy amount of them throughout the day (especially if you are physically active). Consume, at minimum, your RMR in calories and add a couple hundred more to make up for the increase in physical activity you will add in the new year. One of the best things you can do for yourself is eat and eat right; your mind, body and spirit will thank you.