Body Mass Index (BMI) is a reliable guide used by doctors and dieticians. But there can be exceptions. We all have a different amount of muscle - BMI works on the average. In someone athletic or muscular, BMI may overestimate their body fat. Or if the person has lost muscle due to illness or age, BMI could underestimate body fat. Seek your GP’s advice if in doubt.

WORK ACTIVITY LEVEL

LIGHT - Professional and Technical worker, administrative and managerial, Sales reps., clerical and related worker, housewife.

MODERATE - Sales worker, service worker, domestic helper, student, transport worker, some construction work, e.g. joiner, roofer

MODERATE/HEAVY - Equipment operator, labourer, agricultural worker, some construction work, e.g. bricklayer, mason

LEISURE ACTIVITY LEVEL

INACTIVE - driving, cooking, washing up, dusting, cleaning, vacuuming, cooking, playing snooker, bowls

MODERATELY ACTIVE - making beds, painting and decorating, mopping floor, gardening, cleaning windows, playing table tennis, sailing, playing rounders, golf

VERY ACTIVE - Polishing furniture, heavy gardening, chopping wood, volley ball, dancing, cycling, football, tennis, jogging, energetic swimming, skiing

Source: RHSS 41 Dietary Reference Values for Food, Energy & Nutrients for the UK, HMSO 1997

It's tempting to want to lose weight fast, but there are many reasons why cutting down hugely on what you eat isn't good.

1. It's hard to keep up for long and usually ends up in binge eating, leaving you feeling a failure.
2. Your body starts using up its energy stores which includes muscle as well as fat.
3. Your body thinks you're starving it and starts to slow down your metabolic rate to save energy (calories).
4. It doesn't help long term as you're not learning how to eat better for life.

Ideal weight loss is 1 – 2 lbs a week(about 1/2 - 1 kg). The slower you lose weight, the better chance it stays off.