Calories
NHS.UK guidelines suggest that women should consume 2000kcal per day while men should aim for 2500kcal. However, the quantity of calories you should consume will depend on a few factors; the type of training you do, your level of exertion, and your BMR
With high intensity exercise or rigorous weightlifting programmes the body’s demand for energy increases. Having the required quantity of energy from your food means you will be able to perform at your optimum in the gym and maximise your performance. As energy equates to having a more effective workout.
Using the Cronometer app is an invaluable way to track, not just your calories, but all your macro and micronutrients that you consume daily. If you are serious about knowing what your exact nutritional intake actually is, then using resources like cronometer.com removes the guess work. If, for example, you are doing intense training and following your workout programmes to the letter, but you are still finding it hard to shift that stubborn belly fat, it might be wise to look at how many calories you are consuming. And even consider decreasing the quantity or “being in a deficit”.
Caloric Deficit
Being in a caloric deficit is necessary for weight loss, however, reducing calories should not be done in an extreme manner. Drastic calorie reduction/restriction most often has the opposite effect and can lead to vitamin and mineral deficiencies, lack of energy and affect normal hormone production.
A good rule of thumb would be to reduce your calories from maintenance by 50 to 100 kcal and monitor for a week or two how your body responds. Reduce incrementally every couple of weeks until you begin to see the desired results. Bear in mind that a caloric deficit of 500 kcal from maintenance is considered extreme.
Caloric Surplus
At the other end of the spectrum are those who wish to gain weight in the form of muscle mass. With the phrase “bulking” commonly thrown about, it is easy to misunderstand and go over-board. If you find that you are not gaining the mass you want, then a slow increase of calories from maintenance is prudent.
Best practice would be to increase your calories from maintenance by 100 to 150 kcal and monitor for a week or two, increasing incrementally until you begin to see the results you want. A massive jump in calorie intake will result in unwanted body fat and lead to becoming over-weight.