Fad diets under the microscope. Why they rarely last and what works instead
Fad diets give quick results on the scales but rarely last, and the weight often comes back. They cut out whole food groups or promise a shortcut. What holds is less exciting. A balanced plate, steady portions and habits you can keep for years.
A club coach looks at your situation with you and gives you the best advice.
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What the experts warn about
The British Dietetic Association has a food fact sheet on fad diets that lists the warning signs. Stay away from diets that promise a magic bullet without changing your lifestyle, that promise rapid weight loss, that tell you to detox or that rely on liquid meals only. Its advice fits in a single line. If it sounds too good to be true, it probably is.
Popular diets, at a glance
- Very low carb. Cutting out bread, potatoes and pasta brings a fast drop, much of it water. The NHS page on starchy foods reminds us that they contain fewer than half the calories of fat, gram for gram. Our page on starchy foods for weight loss explains how to keep them.
- Detox and juice cleanses. Your liver and kidneys already do this job. Juice brings sugar without much to keep you full.
- Single food diets. Soup, grapefruit or cabbage for a week. Boring, short of protein, and the old habits return on day 8.
- Diets by blood group or gene. The BDA lists these among the claims to be wary of.
Intermittent fasting
Eating within a shorter window can suit some people, mostly because they eat less overall. It is not magic. A long fast can lead to a large meal later, and it is not suitable for everyone, especially if you have diabetes, take medicines or have a history of eating problems. Speak to your GP first.
What holds over time
The NHS 8 tips for healthy eating sound simple, and that is their strength. Base meals on higher fibre starchy foods, eat lots of fruit and vegetables, include more fish, cut down on saturated fat and sugar, do not skip breakfast. These habits do not stop on a Monday. That is why they last.
Most people who have tried diets know the cycle of losing and regaining. Our page on how to avoid yo-yo dieting explains how to break it.
At the club in Witney
At Witney Nutrition Club, members have breakfast at the club in the morning, before work, rather than following a fashionable rule. Your first assessment is free and starts from what you already eat.
This article does not replace advice from your GP or another health professional.
Your weight loss curve
Enter your profile and the curve redraws straight away.
At the median pace, it would take about 11 weeks to lose 8 kg. At the gentlest pace, about 4 months.
The benchmark most often given for lasting weight loss is 500 g to 1 kg a week. That is the ideal zone of the chart. Above 1 kg a week on a regular basis, the body draws on its muscles as much as on its fat. That is the hatched zone.
An indicative projection. Every journey is personal and results vary from person to person. The calculation runs on your device, nothing is saved or sent. Over 65, talk to your doctor first.
How this curve is calculated
The top edge of the zone matches 500 g a week, the gentlest pace. The bottom edge matches 1 kg a week, the risk threshold.
The first weeks go faster, mostly water, then the pace slows. After 40, the median curve slows gradually, because metabolism slows. For the same effort, a man usually loses weight a little faster than a woman.
The journey curve adds plateaus of a few days and small regains, as in real life. It does not predict your own journey.
This advice is general. It does not replace medical advice.
Further reading
For day to day support, see the healthy eating programme.