Can you buy a better body?

So, your beach holiday is fast approaching and you're still bulging out of your bikini. Perhaps it's time to try one of the many weight-loss pills and potions on the market?

Diet System 6

Price: £15.75

Description: A detailed diet and exercise programme with a nutrition supplement. "Permanent weight-loss requires a lifestyle change that you can live with for life... There are no strict calorie-counting charts to follow. All you have to do is eat sensibly and in moderation," the manufacturer says.

The programme advises on diet and suggests at least four hours a week of aerobic activity and at least two hours a week of free-weight or weight-machine training.

One or two of the capsules should be taken before each meal with a glass of water. They contain "Super Citrimax – a valuable, natural diet ingredient derived from fruit extract" (garcinia cambogia HCA extract), "Energising herbs – chosen for their special energising properties" (kola nut extract, ginger and guarana extract), "Chromium Picolinate – chromium is one of the most researched diet ingredients", "Lipotropics, which are included in the breakdown of solid fat so that it can be metabolised by the body", "L-Carnitine – an amino acid used by the body to transport fat to the cells to be burned as energy", and vitamins and minerals.

What the experts say

Catherine Collins (state-registered dietitian and spokesperson for the British Dietetic Association) : The dietary recommendations constitute an energy- reduced diet – without seeing the diet plan recommended, it sounds as though it will be a standard weight-reducing plan. The supplement is chock-full of substances that we know influence metabolism, but nowhere near as spectacularly as the person buying this would expect. We know, for example, that caffeine (main active ingredient in the guarana and kola nut extract) and 'hot' spices can increase the metabolic rate marginally (by a few calories a day) – hardly significant.

Carnitine is produced naturally in the body, and chromium, although important for glucose metabolism, is required in such minute quantities that it is very difficult on a mixed diet to develop anywhere near a deficiency that such a supplement could correct. The bottom line? An energy-restricted diet that is the real cause for weight loss, coupled with a totally superfluous supplement.

Dr Susan Jebb (head of nutrition and health research at the Medical Research Council Recourse Centre for Human Nutrition Research) : The eating plan provides a good foundation for successful weight loss. Exercise is also beneficial, but the recommended levels of exercise are likely to be much greater than most people can initially achieve. There is no evidence that the supplement will make any additional contribution to weight loss. Indeed, scientific studies have demonstrated that HCA, chromium and carnitine do not increase weight loss compared to a placebo.

Adios

Price £9.95

Description: Tablets, one to be taken three or four times a day at meal times, as part of a calorie-controlled diet. They contain butternut, dandelion root and extracts of boldo and fucus. "The ingredients in Adios help you to lose weight naturally by speeding up your body's metabolic rate and stimulating fat metabolism."

What the experts say

CC: Very unlikely for the same reason as stated above. The only reason this would work would be the placebo effect – feeling empowered by taking them would reinforce your commitment to cut down on food.

SJ: Many plant extracts have been claimed to stimulate metabolic rate. For the most part, the effect on energy expenditure of this type of product is usually very small, and much less than can be achieved by short periods of exercise. Any weight loss is more likely to be due to changes in diet rather than the supplement.

Figure trim 8

Price: £6.30

Description: Capsules, one of which should be taken with water 30 minutes before each meal. "Taken as directed you will get a feeling of fullness and be able to eat much less than normal and yet still feel completely satisfied," the manufacturer claims. It adds: "Can help slimming or weight control only as part of a calorie-controlled diet."

The capsules contain vitamin B6, sterculia, apple pectin, boldo extract, l-phenylalanine, kelp powder, dandelion-root extract and cider-vinegar powder.

What the experts say

CC: This works on the principle that distending the stomach with water before a meal takes the edge off the appetite – unlikely if it is taken half an hour before. The more likely claim is that the nutrients have an effect on mood, and that this indirectly influences appetite (think of being very mellow versus very unhappy and wanting to 'reward' yourself with food). B6 and phenylalanine will influence mood, but by how much is debatable. Cider vinegar for weight loss is an urban myth.

Kelp (dried seaweed) should be a rich source of iodine, but it would only be beneficial if you are deficient, and excess iodine can be toxic to the thyroid. Apple pectin and sterculia are natural fibres that are bulking agents, but are unlikely to have any effect on appetite. Dandelion extract may contain inulin – a fibre that is absorbed and excreted in the urine, taking water with it. But again, it is unlikely to be sufficient to create an effect, and in any case this would cause water rather than fat loss.

Bottom line: new age functional foods combined with old wives' suggestions to give a supplement that is unlikely to cause a great increase in metabolic rate.

SJ: There is no scientific evidence that any of the components of this product will help people to lose weight. It does contain some dietary fibre, but there is no convincing evidence that this helps to reduce between-meal snacking. Any effect of the fibre in the supplement could be achieved by choosing fibre-rich foods at meal times.

Bio-Light 3-day three detoxway

Price: £14.20

Description: "Three-day action plan to help you feel great, look good and curb weight." Claims to be a "unique blend of cleansing fruit and vegetable juices, aromatic plants and herbal extracts [which] can provide your digestive system with a kick start, and, when taken in conjunction with the enclosed eating plan, can help your body to better cope with eliminating toxins and stubborn fatty deposits". The solution should be diluted with water, and drunk throughout the day. "Clinical studies have shown that, when taken together with our recommended eating plan, Bio-Light more than doubles the effect of the eating plan on its own, and, by helping to curb hunger pangs and cleanse the system... can assist you in shedding those excess pounds."

What the experts say

CC: Any detox diet and supplement will be so low in energy that weight loss will be forthcoming. The bottom line: new-age detox myth combined with what appears to be fairly standard dietary guidelines for weight loss that do ensure that some dietary protein is consumed. No reason to believe that this [the supplement] has any additional benefit.

SJ: Any 'sensible eating plan' in which calorie intake is reduced to below energy expenditure will lead to steady weight loss. This product claims that it can more than double the rate of weight loss compared to the diet alone which, if true, would be a very dramatic result – greater even than the prescribable medications to treat obesity. However, I am unaware of any published studies showing such an effect.

Slimfast

Price £6.49

Description: Powdered meal-replacement drink. Add skimmed milk. The "classic" plan suggests swopping breakfast and lunch for a SlimFast drink, and eating a balanced low-fat meal in the evening of 600 calories. The one-a-day plan suggests replacing your midday meal with the drink, and adopting their low-fat eating hints and recipes. Each serving contains 200 calories and "all the nutrition you need for a complete meal replacement". Once you've reached your target weight, the manufacturer advises: "Eat less than you did before your diet, and gradually introduce more food into your diet until your weight stabilises." If weight starts rising, go back on the plan for a few days.

What the experts say

CC: This diet works because it removes the dilemma of dieters' choices, and recognises that the failed dieter fails because of lack of willpower. Much as dietitians would prefer people to learn new eating habits, we have to concede that the meal replacement contains many more nutrients than an equivalent 200kcal meal could. SlimFast has recently been shown to keep weight off long-term – no mean feat. The bottom line? Great if you don't mind omitting a selection of foods from your diet each day, being a social outcast at lunch, and the absence of chewing.

SJ: There is clear evidence from formal clinical trials that people consuming SlimFast products do lose more weight than those following a conventional diet, and keep the weight off for longer if they continue to use the product. For some people, a SlimFast drink can be a convenient calorie-controlled meal, giving just 200 calories, perhaps instead of a 400-calorie lunchtime sandwich. The rate of weight loss will depend entirely on the total caloric intake for the day, so to be effective, this must be used sensibly as part of an overall dietary programme.