Do we need to follow a specific diet plan if we want to lose weight? Which diet plans are the most effective? And which are also the healthiest?

  • Is a Mediterranean diet best?
  • Should we avoid celebrity diets?
  • Some diet options worth considering
  • A free weight-loss plan and support from the NHS
  • Conclusions

Is a Mediterranean diet best?

Might it be better to simply eat a balanced and nutritious diet rather than a diet designed to lose weight? The Mediterranean diet, for instance, is rich in fruit, vegetables, cereals and pulses, with olive oil, some fish, cheese and yoghurt but low levels of meat consumption.

That’s what leading doctors recommended in an editorial in the Postgraduate Medical Journal in November 2014, as reported by the BBC shortly afterwards. They advised that concentrating on good nutrition rather than counting calories would not only improve metabolic health in the short term but may also promote sustained weight loss.

A mejor study in the USA, published in 2011, came to a similar conclusion. It followed 120,877 healthy men and women for up to 20 years and found that:

  • consuming more potato chips, red meat, processed meats, alcohol and sugar-sweetened drinks was associated with greater weight gain.
  • eating whole grain foods, vegetables, fruit and yoghurt was associated with weight loss (as was physical activity and six to eight hours sleep per night). 


More recently, a 2016 review of the evidence concluded that after 12 or more months the Mediterranean diet was more effective at reducing weight than low-fat diets and was as effective as low-carb diets and the American Diabetes Association diet.

However, if you feel you need a more structured diet plan than the Mediterranean diet, what are the best options?

Most adults need to eat less and get more active.



Should we avoid celebrity diets?

Yes, according to the British Association of Dietitians, which has produced a factsheet on ‘fad diets’. 

Sadly, there is no magic solution to losing weight and keeping it off long term. There is no ‘wonder diet’ you can follow without some associated nutritional or health risk.

                                                                               British Dietetic Association

The Association warns against the kind of plan where you eat a very restrictive diet with few food types – or an unusual combination of foods – for a short period of time. You may lose weight very quickly, but like many people, you may get fed up with the diet, start over-eating, choose less healthy foods and pile the pounds back on. Conversely, if you continue to follow such a restricted diet, there’s the health risk of missing out on important nutrients.

The NHS reaches a similar verdict and gives five reasons to avoid fad or ‘novelty’ diets:

  • some diets can make you ill
  • excluding foods is dangerous
  • low-carb diets can be high in fat
  • detox diets don't work
  • fad diets are often far-fetched.

Some diet options worth considering

In 2005, Lisa Harkin and Dr Darwin Deen assessed 45 well-known diets in their book Nutrition for Life. They considered three criteria:

  • Is the diet healthy?
  • Is the diet evidence-based?
  • Is the diet likely to be easy to maintain?

Their findings still seem to be valid today and have been corroborated by more recent assessments. Here are short descriptions of five of the diets they rated more highly:


The FatManSlim diet website no longer seems to be available. However, you can find out more about it here 

Unusually, this 12-week diet plan was devised by men, for men. It described itself as a ‘waist loss programme’, as the fat that accumulates around a man’s waist is, medically speaking, the most dangerous. 

FatManSlim is based on the principle that men want to stay in control and make their own changes in private and in their own time.

Harkin and Deen concluded that FatManSlim is balanced and nutritionally sound and will most likely promote weight loss.

Slimming World and Weight Watchers.

Each of these two options (for a fee) offers a structured approach, provides support, encourages exercise and is designed to be reasonably easy to follow.

The Pritikin diet and eating plan

This low-fat, primarily vegetarian diet is based on whole grains, fruits and vegetables combined with an eating plan of three meals a day with snacks between meals. It requires no calorie counting or portion control. The sample menus provide a large variety of nutritional choices. The diet itself is available free online, but Pritikin also has a commercial side operating through its Pritikin resort and online shop.

Harkin and Deen concluded that the Pritikin diet is safe and effective.

Another review of the Pritikin diet explains that it has value in that it aims to encourage exercise and limit sugar intake, but the review cautions that it may not include enough fatty acids or enough vitamins D, E and B12. It may also weaken the immune system.

The review suggests that the Pritikin diet is probably safer for short-term rather than long-term use.


The aim of this programme is to help you feel that you’ve eaten enough by choosing to eat low-calorie foods in quantities that make you feel full, rather than eating the same volume of high-calorie food.

The basic principles of the diet are available free online

Harkin and Deen concluded that the Volumetrics diet is a safe and effective weight-control programme.

Other low-fat diets

A 2020 review of published evidence that compared low-carbohydrate diets with low-fat diets (like the Pritikin diet) concluded that both diets can reduce weight, although low-carbohydrate diets induce greater weight loss. Conversely, low-fat diets were less likely to raise LDL (‘bad’) cholesterol

A free weight loss plan and support from the NHS

If you feel that free support would help you when you’re trying to lose weight, the NHS offers practical support and guidance on health issues and lifestyle matters through local Community Health Trainers.

Try a web search for ‘NHS health trainer’ and add your city, local authority or region to see if this is available near you (for example, search for NHS health trainer Yorkshire) or visit the NHS’s ‘Health Trainers’ website. 

Here’s an example of a programme from Manchester.


  • If you want to lose weight and stay healthy, the best option may be to focus on nutrition and follow a balanced Mediterranean diet.
  • Avoid the more extreme and restrictive diets, even if they are endorsed by celebrities. They are usually hard to sustain, and they can carry health risks if used long term. For instance, you may not get enough important nutrients.
  • If you feel you need to follow a structured weight-loss diet, then some of the more established diets recommended by Harkin and Deen may be worth considering.
  • FatManSlim is one of the few diet plans designed specifically for men. Although its website is no longer available, information about this diet is still available for free.
  • Free support may also be available from the NHS through its local Community Health Trainers.

Reviewed and updated by Kirulagini Sivamathavan and Michael Baber March 2021. Next review, February 2025


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