Energy demands and nutritional goals
Athletes often struggle to identify their energy demands and establish nutritional goals. This article will lead you in the right direction so you can better understand and meet your individual needs.
Let’s start with the basics.
What are calories?
A calorie is a unit of energy. Specifically, 1 calorie is the energy required to raise the temperature of 1 gram of water by 1 degree Celsius. Calories are commonly used to measure the energy content of foods and beverages.
The energy we take in through food is the main fuel of our body. This necessary energy is obtained from the food and drinks we consume through the oxidation of the macronutrients (proteins, carbohydrates, fats) they contain. The amount of energy, i.e. calories (measured in kcal), provided by each of them varies:
Fats have the highest energy density and provide 9kcal/g.
Alcohol provides 7kcal/g.
Protein provides 4kcal/g.
Carbohydrates (starch and sugars) have the lowest energy density and provide ~4kcal/g.
Using these values allows us to estimate the daily energy intake from the food and drinks we consume.
Are all calories the same?
"A calorie is a calorie" which means that all calories yield the same amount of energy from whatever source they come from. However, we should pay attention to the quality of the calories we consume and not exclusively to the quantity. That is because foods that provide the same calories can have completely different nutritional content. Different sources of calories can have very different effects on appetite and satiety, hormones, energy expenditure and metabolism, and areas of the brain that control food intake.
In many cases, simple changes in food selection can lead to the same or better results than restricting calorie intake.
Should I count my calories?
Counting the calories you consume helps you estimate your daily energy intake and has been shown to be helpful in weight loss efforts, but it is not necessary. Using a calorie counter has become quite easy, as there are many tools that by recording the food and drinks you consume you can get an idea of your daily calorie intake.
Using a calorimeter will help you understand the supply of energy to your body by consuming food and drinks, as we know the energy density of the food. For example, foods with high energy density are sweets and fried foods, i.e. foods rich in fats as well as ready-made snacks and junk food. In contrast, foods such as fruits and vegetables, or products with a low-fat content are foods with low energy density.
Counting calories should aim to estimate the portion you consume.
Also, by measuring the energy you take in you can compare it with the amount of energy you need to meet your daily needs and estimate the portions you consume. The goal is to determine the correct portions that you should consume. Once this is achieved, the systematic measurement of the calories you consume is not necessary and in no case should this become an obsession. It is not wise to count your calories with rigor and fear, but do it in the first few days or weeks of your diet to get a sense of the calories you should be eating, and define your meals and portion sizes.
We should emphasize that:
it is not possible to accurately measure the calories of the foods you consume, and
it is not necessary to count how many calories you consume every day to lose or gain weight.
What matters is that you follow a diet that is right for you and your goals, eating foods with high nutritional value that you like and satisfy you.
How many calories do I need to consume daily?
A regular supply of dietary energy is essential for life. Each organism needs energy that it takes in with the consumption of food and drinks (energy intake). Energy is required to power our bodies and maintain our vital functions such as our heartbeat and breathing, organ function, maintaining body temperature, muscle contraction and growth. Daily energy requirements are based on an individual's gender, age, height, and activity.
Due to the uniqueness of an individual, there is no clear answer to the question of how many calories we should take in daily without rigorous metabolic testing. The caloric needs of an adult woman range from 1,600–2,400 calories per day and 2,000–3,000 calories for an adult man [1]. People with high caloric needs such as professional athletes who follow an intense and systematic training program, and even people with physically demanding jobs may need a fairly large number of calories to maintain their weight.
Weight Management
When the immediate energy needs are met, an energy surplus is created which is stored in your body in the form of glycogen in the muscles but mainly as fat tissue.
Weight Maintenance
When the energy your take in through your diet (energy intake) is equal to the amount of energy expended (energy expenditure) through your body's metabolic reactions and physical activity, then the energy balance prevails and your weight remains the same.
Weight Gain
When your take in more calories through your diet compared to your daily caloric expenditure (positive energy balance) your body is in a caloric surplus and an increase in your body weight is achieved.
Weight Loss
In contrast, when you consume fewer calories than the amount that you need to cover your daily energy requirements (negative energy balance), for example when you follow a restrictive diet, your body is in an energy deficit. It is then forced to draw energy from its reserves to replenish and this leads to weight loss.
Maximum fat loss per kilogram of body weight is achieved by combining proper diet and exercise.
The number of calories that our bodies "burn" depends on 3 factors [3]:
The basic metabolism (basal metabolic rate, BMR), i.e. the amount of energy per unit of time that a person needs to keep his body at rest. This amount of energy is necessary for the functioning of our vital organs, such as the heart, lungs, and brain, and supports various processes, such as blood circulation, respiration, regulation of body temperature, cell growth, muscle contraction, and brain and nerve function. Basal metabolism varies between individuals, depending on factors such as sex, age, weight, and body composition, as well as a person's health status, and accounts for approximately 60-75% of daily caloric expenditure. Basal metabolic rate affects the rate at which a person burns calories and ultimately maintains, gains, or loses weight.
The amount of energy spent digesting, absorbing, and storing the food we eat (food-borne thermogenesis). This makes up 10% of our total daily calories.
Finally, another amount of energy that is included in our energy expenditure is physical activity. This constitutes 15-30% and depends on the type, duration, and intensity of the activity.
Now let’s discuss how you should set your nutrition goals based on the things that you just read.
Nutritional goals
There is rigorous science behind the principles of sports nutrition and its application in training and competition settings. However, the cornerstone of a good training diet starts with laying the foundation of healthy eating by following key messages and better dietary practices. Recreational or elite athletes partaking in sports and exercise will be presented with nutritional challenges. For example, athletes need to meet high energy demands placed by high-intensity exercise, prolonged strenuous exercise, or repeated bouts of exercise, require practical skills regarding food preparation, plan for multiple competitions and know what to eat when traveling to unfamiliar destinations. Strategies that can achieve a number of nutritional goals at the same time are most useful to help athletes integrate separate issues and save time and resources.
The ultimate aim of any sports and exercise nutrition professional would be to convey their knowledge of nutritional science into real food and fluid choices for the athlete. Athletes want accessible and appetizing food and fluid options. Determining menus and recipes for athletes is one method to make sure of appropriate food selection, while planning an individualized supplement program may help athletes to weed out the plethora of expensive and non-beneficial supplements that bombard the sports market.
The training or foundation diet holds the key to overall exercise performance. The nutritional goals of the athlete’s foundation diet are:
to meet their basic energy and nutrient requirements,
to promote immediate and long-term health and longevity,
to achieve and maintain a healthy body mass and acceptable level of body fat and lean body mass,
to promote optimal performance and recovery, and also
to accommodate appropriate and beneficial experimentation with competition nutrition strategies.
Food is meant to nourish and be enjoyed, but many athletes worry about the adequacy of their diets. The foods, fluids, and any supplements that the athlete chooses should be enjoyable, and not merely because it is prescribed or based on an anecdote from a well-known competitor or a performance-enhancing theory. If food items are chosen merely for their performance-enhancing abilities, it may introduce a restricted diet that is not very accessible and may be dull and unappetizing. Compliance with such an eating plan may be low, and in the long-term health could suffer. As with the general population, it is advisable that athletes eat a variety of foods. Each food group has a range of nutrients, some with a known role in sports and exercise. Eating daily portions from each group will help fulfill the daily recommended nutrient intake levels for optimal nutritional status, health, and exercise performance.
Basic points
Your body gets the energy it needs to stay alive, move and grow, through the food and drinks you consume.
Energy requirements vary between individuals and are based on factors such as age, sex, weight and height, and level of physical activity.
In order to maintain body weight, it is necessary to achieve energy balance, i.e. the energy coming from food is balanced with the energy expended. For weight loss, energy expenditure should exceed energy from calorie intake, while for weight gain, energy intake should exceed expenditure.
References
[1] Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington (DC): The National Academies Press; 2002. https://health.gov/our-work/food-nutrition/2015-2020-dietary-guidelines/guidelines/appendix-2/
[2] Frayn KN (2013). "Chapter 11: Energy Balance and Body Weight Regulation". Metabolic Regulation: A Human Perspective (3rd ed.). John Wiley & Sons. pp.329–349. https://books.google.co.uk/books?id=SdQ9NPIzMmsC&pg=394&redir_esc=y#v=onepage&q&f=false
[3] Poehlman ET. A review: exercise and its influence on resting energy metabolism in man. Med Sci Sports Exerc. 1989;21(5):515-525. https://pubmed.ncbi.nlm.nih.gov/2691813/
