Understanding the energy equation and how to alter it in order to promote weight loss instead of weight gain is the key to reaching a healthy weight. Knowing the facts can be the basis of taking control of your weight and staying motivated throughout a safe and steady weight loss campaign.
The last section looked at the energy equation and the different factors that can affect it. Now the time has come to apply those principles to individual circumstances.
must know
Calories
One calorie (4.2 joules) is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Centigrade. Nutritionists measure the calorie values of foods by burning them in a calorimeter to see how much heat they give off. The major food groups differ in ‘energy density’ –the number of calories they contain per gram:
Altering the energy balance
The next few pages set out how far to reduce your calorie intake and increase your calorie output in order to create your own personalized slimming plan which will guarantee safe and steady weight loss.
As the previous chapter showed, the science behind weight loss and weight gain is all about the energy equation: consuming more energy, in the form of food, than is expended in activity results in weight gain. To lose weight, it is essential to create an ‘energy deficit’ so that more energy is expended in activity than is taken into the body as food.
Units of energy
The units of energy used to measure this process are kilojoules or calories – the word that can be very off-putting for people who have followed the kind of diet that requires the counting and measuring of every single mouthful they consume. Unfortunately, it is impossible to ignore calories when trying to lose weight. It is true that there are plenty of diets that promise you ‘need never count another calorie’. This is generally because they either give calories another name, such as ‘units’, or because they ensure that calorie intake is controlled automatically by limiting the kinds of foods that can be eaten.
Calculating your energy deficit
The aim of this section is to show you how to calculate a personalized energy deficit by working out:
Inevitably, this means talking about calories. However, it is possible to lose weight easily by being calorie-conscious and without having to become a calorie slave
must know
Calorie guides
Buy a calorie counter book for an at-a-glance guide to thousands of everyday foods. These are available at most newsagents and bookshops. Don’t guesstimate!
Bulky, watery foods like salad vegetables make good low-calorie fillers in a slimming diet.
must know
Diet or exercise?
When thinking about losing weight, men and women tend to have different approaches: women say it’s ‘time to start the diet’ and men say it’s ‘time to hit the gym’. It is perfectly possible to create an energy deficit by changing your diet alone, or just by doing a lot more exercise (although the exercise-only route is slower). The perfect combination for health and weight loss is to do both: to make some small changes to your diet, and to become a bit more active as often as possible.
Where does it all go?
The body uses the food we eat in three main ways: for growth; to replace damaged or worn-out tissues; and to fulfil all the body’s daily functions, which can range from breathing to ballroom dancing. The amount of energy needed from food to keep the body going, without gaining or losing weight, is called the basal metabolic rate (BMR). Any energy (calories) which is taken in over and above the requirements of the BMR is stored – and, as the last chapter showed, this is one thing at which the body is very efficient.
Once food has been digested, any surplus energy is stored either as glycogen – a short-term energy source, which is stored in the liver and the muscles – or as fat, which is stored in ‘fat depots’ under the skin, around the kidneys and in the abdomen. There is a limit as to how much glycogen can be stored before it is released back into the bloodstream to be used, but there is no limit to the amount of fat that can be stored. Fat cells get bigger, multiply and form adipose tissue which can eventually present a threat to our health.
It takes about 3,500 calories surplus to the requirements of the BMR to create 1lb (454 g) of stored energy (otherwise known as fat). So an individual whose BMR is 2,500 calories per day, and who eats 3,000 calories’ worth of food per day without changing his or her activity level in any way, could expect to put on a pound a week (7x500 = 3,500 calories). In practice, our body weight fluctuates from day to day and even at different times of the day, which is why it is best to weigh yourself only once a week at the same time –jumping on the scales more often can be misleading. However, overtime, a steady over-supply of calories without an increase in activity to compensate will surely result in a weight gain.
Healthy home-grown vegetables: fantastic for taste,