Sticking to a new diet or fitness campaign can be a complex task. Many people think starting is the hardest step, but in my experience lack of support from those around you is often the reason the best-laid plans go pear-shaped.

Some won't like your diet because they hate change. Others may be reminded of their own irresponsibility when it comes to diet and exercise. Then, of course, there are those who fear you may become more attractive to the opposite sex.

And now science proves how friends and family can ruin your diet. A recent study by The New England Journal of Medicine has discovered that a person's chance of becoming obese increases by 57 per cent if they have a friend who becomes obese, 40 per cent if a sibling becomes obese or 37 per cent if their spouse becomes obese.

Behavioural counsellor Christine Sutherland says one way to stop the problem is to not answer or debate people's negative comments.

'If you do, all you're likely to get is an argument,' she says. 'Instead, respond with questions asking for more information and eventually, usually out of frustration, they'll give up.'

Saying 'no' to dessert
When it comes to handling a pushy friend who's trying to get you to have dessert, and you don't know what to do, there are a few choices.

If your health kick is on track and you're really making an effort, just say 'no' without any explanation. You don't have to justify yourself and often a flat 'no' is the best way to be heard.

Alternatively, you can eat up. If you want some, enjoy it, but treat the occasion as the exception rather than the rule.
Lastly, you can say 'yes' but let the dessert sit there. Most people are so preoccupied with themselves they don't notice
if you're eating or not. Later on, slip it into the pile of dishes to be cleared and washed up.

More diet saviours
At dinner parties, it's often difficult to stick to your resolve. If people are trying to fill your glass, tell them you're driving, or simply put your hand over your glass and say 'no'. When your partner's eating pizza, it doesn't mean you have to. But if you can't resist, gradually encourage your partner to make healthier choices such as a vegetarian thin crust pizza once a fortnight, instead of the thick crust one loaded with bacon and salami every second night.

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