1 Ease off the booze

Alcohol acts like a plug in your bloodstream (a burping, slightly rowdy plug) because it stops your body burning fat as fuel, undoing all the good work done by your healthy diet and exercise regime. Long-term heavy drinking also causes muscle loss, leading to further weight gain because muscles help us burn calories.

2 Ditch the fruit juice

No, we haven’t taken leave of our senses and yes, fruit juices are full of vitamins and minerals, but they do contain a fair amount of calories too – a 250ml glass of fresh orange has around 100. Eating the fruit itself will give you all the goodness of the juice plus a lot more fibre, which fills you up and makes you less likely to crave snacks later.

3 Do lots of exercise

We would say that, wouldn’t we? When you work out, your metabolic rate rockets as much as 15 times, depending on how hardcore your session is. Once you stop exercising your metabolic rate stays high too, so frequent exercise will keep you firing on all fat-burning cylinders for longer.

4 Cook up a storm

People who cook for themselves weigh less than those who regularly eat out, according to researchers at Tufts University in the US. Eating at home tends to involve smaller portions, less fat, less obligation to finish every last scrap on your plate and fewer jumbo ice cream desserts.

5 Keep a diary

But instead of writing down your darkest secrets, such as what you’d really like to say to that girl in the finance department, record your daily calorie intake and exercise. It’ll keep you motivated and help you avoid slipping back into old bad habits.

6 Swap white bread for brown

Foods made with white flour – such as pasta, white bread and white rice – cause your energy levels to rise rapidly and then dip, leaving you hungrier than you were in the first place. Rye bread and wholemeal flour products, such as pittas, wholemeal pasta and brown rice, will keep you fuller for longer. If you’re not sure about the taste, try mixing white and brown rice or pasta and go for multigrain bread.

7 Go easy on the post-swim snack

Swimming is often touted as the best sport for weight loss because it burns four times as many calories as running, but research suggests some people get so hungry after a dip they reverse most of the benefits with a massive meal, whereas runners and cyclists tend to feel a drop in appetite following a workout. Don’t let this keep you out of the pool, but keep an eye on your portion sizes.

8 Don’t cut out all fat

You have to eat less of it to lose weight but good fats, such as those found in nuts, avocados, olive oil and oily fish, are essential for health and can help you lose weight and lower cholesterol. It’s the saturated fat you need to avoid.

9 Get on your bike

Cycling to work is a great way to fit exercise into a hectic schedule, but if that’s not practical make time for it at the weekend. A five-mile bike ride can burn up to 600 calories and 20 miles, even at a moderate pace, can burn 900 – the equivalent of a lamb biryani from the local curry house.

10 Downsize your dinner

One simple way to lose weight is to, well, eat less. Smaller portions will cut your calorie intake, and one way to ensure you don’t overeat is to use smaller plates. It’s psychological, but it works.

11 Buy some scales

Not for your bathroom, mind – get a set for your kitchen. This is another way to make sure you keep your portion sizes in check.

12 Racket up

Don’t be put off by Andy Murray’s scary temper and faux-Afro – one hour of tennis burns a whopping 450 calories, which is the equivalent of four and a half bananas. For more information about the LTA’s free tennis days visit www.playtennis.org.uk.

13 Have a good breakfast

Starting the day with a good meal boosts your resting metabolic rate by ten per cent, according to a study in the American Journal Of Clinical Nutrition. Other research shows that people who skip breakfast have lower metabolisms, which makes it harder to shift weight.

14 Drink iced water

Your body will burn calories warming up the water to body temperature – every little helps.

15 Always exercise on a Monday

It’s the most important session of the week because it gives you a great psychological boost that will fire up your exercise regime and keep you eating the right foods for the rest of the week. Besides, what else is there to do on a Monday night?

16 Fuel your workouts

To get the maximum benefit out of your Monday workout you need to eat the right balance of foods. Ignore evil fad diets and eat around 65 per cent carbs, 15 per cent protein and 20 per cent fat. If you don’t fuel your workout properly you will end up burning muscle rather than fat.

17 Don’t depend on sweeteners

Substituting sugar with artificial sweeteners may not aid weight loss because they can cause youto crave more food later, according to studies from the University of Swansea. The research, reported by awareness group Carbs For Life, suggests cutting down on fat rather than sugar is the best method for weight loss.

18 And… relax

Stress produces the hormone cortisol, which causes the body to store fat, usually around the waist. Exercise is an excellent way to reverse this process because it helps you lose weight and releases feel-good endorphins in your brain. Brisk walking, deep breathing and meditation can all aid relaxation too, and so can getting out in the sunshine. If you can find any.

19 Switch your running surface

Running on grass, sand or dirt surfaces makes you work a lot harder than you would if you were pounding the pavements or treadmill. Soft sand is best, helping you burn up to 50 per cent more calories than you would running on concrete. Adding an incline burns 15 per cent more calories.

20 Drink green tea

It’s been proven to aid weight loss, thanks to a combination of caffeine and phytochemical catechins, which help speed up your metabolism. Four cups a day can help you burn an extra 60 calories without you even having to break into the faintest of sweats.

21 Balance your energy

To lose weight you need to burn more calories than you take in. It really is that simple, no matter what the plethora of miracle diets or pills and potions available may tell you.