Burning Calories

How calories work, how many you need to maintain a healthy weight and why too few can make you fat!

Energy is needed for the body to function and be active. The body derives its energy source from carbohydrates, protein and fats and alcohol in the diet. Energy is measured in heat units called calories.

What are calories?
A calorie is the amount of heat required to raise the temperature of 1g of water by one degree Celsius. This is a very small unit and so energy derived from food is expressed in units that are 1,000 times larger, known as kilocalories.

Calories are required by the body to function. Even when we are sleeping we need a significant amount of calories. This is known as base metabolic rate (BMR) and is determined by body weight and composition, which can vary with age and sex. Calories are also needed for physical activity.

Government guidelines for energy requirements are:

Age Male Female 19-49 2550 kcal 1940 kcal 50-59 2550 kcal 1900 kcal 60-64 2380 kcal 1900 kcal

If more energy is received than is used, excess is first stored in the liver and muscles as glycogen and then in dispossed tissue as fat.

Conventional theory states that to lose weight there must be a reduction in calories and/or an increase in activity. One pound of fat is said to be the equivalent to 4,000 kcal.

The type of food and how we eat must also be considered. Very low-calorie diets - below 1,000 calories per day - have shown to have a poor success rate over the long term.

Low calorie levels increase weight
On low-calorie diets the body will start to use muscle tissue for energy in preference to fat stores. Therefore, vital muscles - such as those around the heart - will be lost before fat.

Much of the initial weightloss on restricted calorie diets will be from loss of water. For every molecule of glucose, you lose three times the amount of water. And this will go back on three times as quick!

Ideal weightloss
The best programme is one where you only lose around 1-1.5lbs each week, and which is fat loss, not water and muscle.

One good thing about calorie counting is that it makes you aware of how much fat there actually is in much of the food you eat. Fat should be reduced in our diets but we do need a certain amount of fat to produce essential acids, build hormones, maintain the immune system and absorb vitamins. Fat is also your powerhouse of energy when embarking on high-energy exercise regimes.

Aerobic exercise like running, tennis, squash, group fitness classes and dancing could burn up to 1,000 calories. This, combined with a sensible low-fat, sugar and alcohol-free diet, maintained over a long period, will give you excellent long-term results.

Consume more: fruit rice pasta water low-fat dairy products lean meat

Consume less: full-fat milk cheese red meat butter cakes, biscuits, chocolates, etc alcohol

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