Calories – a term most people have heard of but one that not many of us actually know much about.
So, let’s take a look:
What is a calorie
A calorie is a unit of measurement – in the case of food and drink, the measure of the amount of energy it contains.
On average, adult males need around 2,500 kcal a day to maintain a healthy body weight. For women, the figure is around 2,000 kcal a day. These figures vary, depending on size, age and levels of physical activity, amongst various other factors.
Calories and energy balance
Like everything else on our planet, the human body requires energy in order to function. It gets that energy from the food and drink we ingest. The energy is necessary for everything we do – all movements, breathing, sleeping, maintenance of internal body systems, plus a million and one other things.
To maintain a stable weight, the amount of energy we put into our bodies in the form of calories must be equivalent to the amount of energy needed by the body. An essential part of a healthy diet is achieving that balance, i.e. taking in just enough calories to function efficiently and no more.
Get the balance wrong though and one of two things will happen. If the body gets less calories than it needs, it is forced to get energy from its fat stores and muscle tissue. As a result, it loses weight. If the body gets more calories than it needs, on the other hand, rather than throw the excess energy away, it stores it in the form of fat for a rainy day and so gains weight.
How to check calorie intake
From the above, it should be clear that we need to know the calorific content of the food we eat in order to get the balance right. To assist us in this respect, the calorie content of most shop-bought foods is stated on the food information label.
The amount of calories people use by doing a particular physical activity varies, depending on a range of factors that include gender, size and age. The more vigorously an activity is carried out, the more calories will be used. For example, running will burn more calories than walking.
If someone is gaining weight, it means they have been eating and drinking more calories than they’ve been using. To address the problem, they need to use more energy than they consume for as long as it takes to lose the excess weight. They can do this either by reducing their calorie intake (eating less), or burning more calories (exercising more).
The best approach is a bit of both – eat less and exercise more