Whether your goal is to lose weight, gain weight or simply maintain your weight, you need to control your calorie intake. When attempting to lose weight, you need to be in a calorie deficit (calorie output greater than calorie input), and if you are aiming to gain weight you need to be in a calorie surplus (calorie input greater than calorie output).A calorie balance refers to the difference between what you eat and what your burn. Your calorie balance is what ultimately determines your weight! Remember that exercise also ‘burns’ calories, which will affect your calorie balance (i.e. calorie output). Your total daily energy expenditure (TDEE) therefore refers to how many calories you burn per day with all exercise and activity considered.
A calorie deficit refers to the state in which you are ‘burning’ more calories than what you are consuming. If your goal is to lose weight, then you need to be in calorie deficit, when in a calorie deficit state, your body needs to make up the difference of what you’re burning and eating. Let’s say you’re burning approximately 2500 calories a day and only consuming 2000 calories, there is a 500-calorie difference that your body needs to substitute for. Where will your body get that 500-calorie difference from? Most likely from your fat reserves! Body fat is stored energy that was created in times of calorie surplus, when you are in a calorie deficit, your body starts to draw from your stored fat for energy. Over time this process will cause you to lose weight.
In contrast, a calorie surplus refers to the state in which you are consuming more calories than you are burning. If your goal is to gain weight, the you need to be in a calorie surplus. When in a calorie surplus state, your body takes the excess energy and uses it to either help you to gain muscle mass (if you are training for that purpose) or accumulate body fat (if you are, for example, less active). When weight training, you damage the muscle tissue (causing micro-tears)your body then repairs the muscle tissue during times of rest (i.e. during sleep). This process leads to increased muscle mass (muscle hypertrophy) and strength. Your body’s muscle recovery process is very energy intensive, which is why you need to consume more than you burn (calorie surplus). A calorie surplus fuels muscle growth, without the extra energy, muscle gain would be a lot harder to achieve.
The first step when creating/choosing a diet for either weight loss, weight gain or weight maintenance is to calculate just how many calories you need to be ‘burning’ in order to achieve your goals. (Shown below) Keep in mind that this will be an approximation.
TDEE = basal metabolic rate + thermic effect of food + non-exercise activity thermogenesis + thermic effect of activity
While the calculation to determine the amount of calories you require can be quite complex, there are many calorie tracking apps that can simplify this for you, and allow you to track your calories with relative ease!
Foods are generally broken down into 3 main macronutrients. Carbohydrates, proteins, and fats. As a rule of thumb, one gram of carbohydrate and one gram of protein each equate to approximately 4 calories, whereas one gram of fat equates to around 9 calories.
The next step is to eat the correct amount of food according to your goals – depending on whether you need to be in a calorie deficit or surplus. Remember, a calorie deficit does not mean you have to starve yourself! You should still eat balanced meals throughout the day, it just means that you will need to calculate your macronutrient and calories intake for each meal to ensure that you stay within your calorie limit. Similarly, when in a calorie surplus, it does not mean you should eat junk food and sweets, as you still need to maintain a healthy lifestyle and consume balanced meals. You will, however, likely need to increase the portion sizes or the amount you eat per day to make sure you are above your maintenance.