And in the same way, creating an energy deficit, so that more energy is expended than the BMR requires, will equally surely result, overtime, in weight loss. So, again, someone whose BMR is 2,500 calories and who eats 2,000 calories’ worth of food each day could expect to lose a pound a week.
Find your balance
There are four steps to working out your basal metabolic rate (BMR):
1 Assessing the resting metabolic expenditure (RME).
2 Making an allowance for activity.
3 Adding in 10 per cent for the energy used in digesting food.
4 Totalling it all up.
As you will see from the instructions and the example given below, this is much easier than it sounds.
Step 1
Use the table to read off your RME. The differences in the table are accounted for by gender and age: generally, men need more calories than women to maintain their weight because they have a higher percentage of muscle tissue, which burns fuel more efficiently than fat. Age is a factor, too, because the amount of energy the body needs for maintenance peaks at the age of about 25 and declines gradually after that, at a rate of about two per cent per decade.
Your RME
| Age – Men | RME equation |
| 18–30 | 15.3 x weight (kg) + 679 |
| 30 –60 | 11.6 x weight (kg) + 879 |
| 60 and above | 13.5 x weight (kg) + 487 |
| Age – Women | RME equation |
| 18–30 | 14.7 x weight (kg) + 496 |
| 30 –60 | 8.7 x weight (kg) + 829 |
| 60 and above | 10.5 x weight (kg) + 596 |
Step 2
Factor in your activity level, based on what you normally spend most of the day doing. The guidelines and calculation are as in the table opposite (top).
Multiply your RME from Step 1 by the activity factor to find the number of calories needed for activity each day.
Your activity level
| Usual daily activities | Activity Level | Activity Factor | |
| Desk job or light housework; driving; reading; watching TV | Very light | 0.2 | |
| Childcare; light exercise, e.g. walks; moderate housework; light manual work, e.g. mechanic, waiter | Light | 0.3 | |
| Moving about all day; spring-cleaning; heavy gardening; active sports | Moderate | 0.4 | |
| Heavy manual work, e.g. building, digging high-energy sport, e.g. football | Heavy | 0.5 |
Step 3
Add together your RME figure and your ‘activity calories’ figure and divide by 10 to find the calories needed for digestion.
Step 4
Add together your RME figure, ‘activity calories’ figure and ‘digestion calories’ figure in order to find your BMR (basal metabolic rate) – the total number of calories that are needed each day to maintain your weight.
To lose weight steadily, the best combination is to reduce your calorie intake and to increase your calorie expenditure by making changes to your daily diet and activity levels.
must know
Working out BMR
Jane is a 30-year-old mother of two with a part-time office job. She weighs 76 kg (12 stone).
Keeping a food diary
Having worked out how many calories you need to maintain your current weight, the next step is to work out how many calories you are taking in as food. Nutritionists recommend that the best way to do this is to keep a food diary. To get a full picture of calorie intake it is important to keep the diary for at least a week, or longer if you feel it would be helpful. Keeping a food diary sounds easy but, in practice, researchers have found that people who are asked to record their food intake almost always under-report what they actually eat. However, to identify patterns of where calories are coming from and where easy savings can be made, it is important to be as detailed and honest as possible – after all, no one else will see the diary. It is also important to eat and drink exactly as usual and not to change your normal routine in any way, as you need to keep track of all the occasions during the week when you might have an opportunity to save calories.
must know
Calorie savings
Look over your food diary to identify the areas where it would be easy for you to make calorie savings.
Sample food diary for a single day
Breakfast
Med egg, 2 rashers back bacon, 1 tbsp vegetable oil, 2 slices white toast, 2 tsp butter, 200 ml glass orange juice, 2 cups tea, whole milk, 2 sugars
Lunch
100 g chicken, 15 cm baguette with 1 tbsp mayo, 25 g packet plain crisps, apple, 2 cups tea, whole milk, 2 sugars
Dinner
225 g grilled rump steak, 225 g jacket potato, 1 tbsp butter, 2 tbsp poached mushrooms, 1 grilled tomato, medium bowl strawberries, 2 tbsp double cream
Snacks/drinks
2 cups coffee, whole milk and 2 sugars; 2 chocolate digestives; 2 x 175 ml glasses red wine; 1 glass water
Total calories per day: 3,048
At this pre-weight loss stage your aim is just to observe everything you eat and drink over the diary