Which diet is right for you?

It's January and time for the obligatory detox. But with so many diet books weighing down the bookshelves, which one will provide the quickest results Alice Hart-Davis presents a guide to the best - and worst - diets of 2005...

GLYCAEMIC DIETS

The (revised) GI Diet, by Rick Gallop (Virgin Books, £10.99). Published tomorrow.
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What it promises:
You will lose weight without feeling hunger, increase your energy and lower risks of heart disease, stroke and diabetes.
How it works: You need to learn about the glycaemic index of foods, which measures how fast your body breaks down carbohydrates and converts them to energy-giving glucose. By eating foods which break down slowly (such as apples or beans) rather than ones which break down fast (white bread, baked potatoes, cornflakes, watermelon), you can stabilise your blood sugar levels, feel healthier and lose weight.

Foods are labelled red, yellow and green to indicate, respectively, those to avoid, to eat occasionally and to eat as much as you want. "The lower the GI of carbohydrates, the better," says Jon Cossins, group health and fitness trainer for Livingwell Gyms, who emphasises that GI Indexing is "the new key factor in fat/weight control".
Chances of success: Requires a whole new way of looking at what's good (like new potatoes) and what's bad (mashed potatoes).

The Low GI Cookbook, by Louise Blair (Hamlyn, £9.99). Published 15 January.
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What it promises: Makes the GI life easy.
How it works: Learning about the glycaemic index is all very well; applying it to your home cooking can be more tricky. Here's a book of recipes to show you how.
Chances of success: No problem. Recipes such as blue cheese soufflé with chicory-and-walnut salad look far too delicious to be good for you.

The GL Diet, by Nigel Denby (John Blake Publishing, £10.99). Out now.
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What it promises: An easy weight-loss plan for life.
How it works: Forget GI - it only gives half the picture. What you need to know is the "Glycaemic Load", which better reflects a food's effect on your biochemistry. Think "filling carbs" rather than "fattening carbs" and you're getting there. Also necessary are good-quality protein, plenty of vegetables and "good fats", eaten in small portions regularly.
Chances of success: Simpler than GI, and makes better sense to those who can't see why GI diets think that carrots, which are clearly good for you, load up the carbs.

The Holford Diet, by Patrick Holford (Piatkus, £7.99). Out this month.
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What it promises: Lose fat fast with Holford's fat-burner system.
How it works: Another glycaemic loading diet: gain control of your blood sugar levels and burn fat by counting the GL content of food, combining protein and carbohydrates
Chances of success: Good, once you learn to count GL points.

LATEST FAD

The Coconut Diet, by Cherie Calbom (Cygnus Books, £5.99). Out now.
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What it promises: Eating plenty of unrefined coconut oil will make your body burn fat faster and lower cholesterol levels. Huge new diet fad in the US.
How it works: Virgin, unrefined coconut oil, far from being a dietary baddie (as has been assumed for many years), actually speeds up the metabolism and thyroid function. Use it as part of a low-carb, high-protein diet for all-round health and weight-loss.
Chances of success: Dubious. You have to stomach oily high-protein, low-carb meals.

SURVIVAL OF THE FITTEST

The Ultimate New York Body Plan, by David Kirsch (McGraw-Hill, £12.99). Out now.
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What it promises: You don't need liposuction - only two weeks' hard effort.
How it works: Toughens you up. Kirsch, favourite trainer of actors and supermodels such as Liv Tyler and Heidi Klum, offers a very low carb diet involving 60-90 minutes a day of exercise, both muscle-sculpting and cardiovascular work - plus relentless motivation.
Chances of success: Only if you're very determined.

DIET FOR BLOKES

The Abs Diet, by David Zinczenko (Rodale/ Pan Macmillan, £12.99). Out now.
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What it promises: Zinczenko is the editor-in-chief of Men's Health magazine. His six-week plan is intended to flatten your stomach and keep you lean for life.
How it works: Involves six meals a day, lots of protein, little in the way of refined carbs, and full-body workouts after the first two weeks. Chances of success: You need superhuman commitment, but it all make sense.

SANE AND SENSIBLE

The Perfect Fit Diet, by Dr Lisa Sanders (Rodale, £12.99). Out now.
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What it promises: Create your own diet, and weight loss will follow.
How it works: Shows you how to work out the regimen, given your food preferences, medical history and lifestyle.
Chances of success: Good, though there's a huge questionnaire to work through.

The Food Doctor Everyday Diet, by Ian Marber (Dorling Kindersley, £12.99). Out 6 January.
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What it promises: More energy, plus weight loss.
How it works: By eating small, frequent meals which combine protein and complex carbohydrates, you will eat well and lose weight without feeling hunger.
Chances of success: High, not least because of its "80/20 rule", which means you choose well for 80 per cent of your meals, and the rest of the time you can please yourself.