Fad & Short-Term Diets: Overview and Risks
Last updated: 20 February 2026
Fad diets and short-term diets are eating plans that promise quick weight loss, often with strict rules or a single “magic” food. Examples people search for include the HCG diet, cabbage soup diet, cabbage diet, grapefruit diet, 3 day diet, 17 day diet, GM diet, GM diet plan, soup diet, cookie diet, egg diet, water diet, fruit diet, Scarsdale diet, oatmeal diet, salad diet, rice diet, chicken and rice diet, apple diet, and meat and fruit diet. We do not recommend fad or short-term diets. They are often very low in nutrients, unsustainable, and can be dangerous (e.g. the HCG diet). This page explains what these diets are, why they are risky, and what to do instead. Always talk to your doctor before starting any diet.
Disclaimer: This page is for education only. DietaBest does not recommend or endorse any fad or short-term diet. Many are unsafe or ineffective. For weight loss, use a sustainable approach with your doctor or dietitian–see our weight loss diet and calorie deficit guides.
Below you will find what fad diets and short-term diets are, examples such as the HCG diet, cabbage soup diet, GM diet, grapefruit diet, 3 day diet, 17 day diet, and others, why we do not recommend them, and safer alternatives. For sustainable weight loss, use our calorie calculator and TDEE calculator with your doctor or dietitian.
What are fad and short-term diets?
Fad diets are eating plans that become popular for a time and usually promise fast or dramatic results. Short-term diets are meant to be followed for only a few days or weeks. They often share these traits:
- Very low calories or extreme restriction (e.g. cabbage soup diet, 3 day diet, water diet).
- Focus on one or few foods (e.g. grapefruit diet, apple diet, egg diet, oatmeal diet, rice diet, salad diet, soup diet, fruit diet).
- Strict daily rules (e.g. GM diet, GM diet plan, 17 day diet, Scarsdale diet).
- Claims that one food “burns fat” or “detoxes” (e.g. grapefruit diet, cabbage diet)–these are not supported by science.
Examples include the cabbage soup diet (cabbage soup plus a few foods for about a week), the grapefruit diet (grapefruit with meals for supposed fat burning), the 3 day diet (very low calorie for three days), the 17 day diet (phased plan), the GM diet or GM diet plan (different food groups per day over seven days), the Scarsdale diet (strict low-calorie plan), the soup diet, cookie diet (replace meals with special cookies), egg diet, water diet (extreme water focus), fruit diet, oatmeal diet, cabbage diet, salad diet, rice diet, chicken and rice diet, apple diet, and meat and fruit diet. The HCG diet combines very low calories with the hormone HCG and is dangerous and illegal for weight loss in many places. We do not recommend any of these.
How fad diets are supposed to work (and why they fail)
Fad and short-term diets often lead to weight loss simply because they are very low in calories–not because of a special food or rule. The grapefruit diet does not “burn fat”; the cabbage soup diet and 3 day diet work by severe restriction. When you stop, weight often returns because the diet is not sustainable and no lasting habit change was made. Some plans (e.g. HCG diet) also use hormones or supplements that are unproven or dangerous. Sustainable weight loss comes from a moderate calorie deficit and a balanced diet–see our weight loss diet and calorie deficit diet guides. Use our TDEE calculator to estimate your needs.
Examples of fad and short-term diets (for information only)
This table lists examples people often search for. We do not recommend following any of them.
| Diet (examples) | Typical claim or approach | Why we do not recommend |
|---|---|---|
| HCG diet | Very low calories + HCG hormone | Dangerous; HCG not approved for weight loss; illegal in many countries |
| Cabbage soup diet, cabbage diet, soup diet | Eat cabbage soup (and a few other foods) for ~7 days | Very low nutrients; unsustainable; weight regain likely |
| Grapefruit diet, 3 day diet, apple diet | Focus on one fruit or very low calories for a few days | No “fat burning” food; extreme restriction; nutrient deficiency |
| GM diet, GM diet plan | Different food group each day over 7 days | Very restrictive; low protein; not sustainable |
| 17 day diet, Scarsdale diet | Strict low-calorie phases or rules | Too restrictive for long-term; weight regain common |
| Egg diet, oatmeal diet, rice diet, salad diet, fruit diet, chicken and rice diet, meat and fruit diet, cookie diet, water diet | Heavy focus on one or few foods | Unbalanced; nutrient gaps; not sustainable; some (e.g. water diet) can be dangerous |
Risks: why we do not recommend fad or short-term diets
Main concerns:
- Too few nutrients: Plans like the cabbage soup diet, 3 day diet, GM diet, fruit diet, or egg diet can be very low in protein, healthy fats, or vitamins and minerals. This can cause fatigue, weakness, and is not safe for extended use.
- Weight regain: When you return to normal eating, weight often comes back because the diet was not sustainable and no healthy habits were built.
- Dangerous plans: The HCG diet is associated with serious risks and is not approved for weight loss. Extreme water diet or very low calorie plans can cause electrolyte problems or other harm.
- Disordered eating: Strict, short-term cycles can encourage an unhealthy relationship with food in some people.
We do not recommend fad or short-term diets. For weight loss, work with your doctor or a dietitian and use a sustainable calorie deficit with a balanced diet. See our weight loss diet and calorie deficit diet guides and our calorie calculator and TDEE calculator.
What to do instead
For lasting, safe weight loss:
- Use our TDEE calculator to estimate your calorie needs, then create a moderate deficit (e.g. 300–500 kcal per day) with our calorie deficit calculator.
- Eat a balanced diet with enough protein, vegetables, whole grains, and healthy fats–see our weight loss diet and calorie deficit diet guides.
- Avoid the HCG diet, cabbage soup diet, GM diet, grapefruit diet, 3 day diet, 17 day diet, and other fad or short-term plans. If a plan sounds too good to be true, it usually is.
- Talk to your doctor or a dietitian before starting any diet, especially if you have a health condition.
Frequently asked questions
Fad diets are eating plans that promise quick or dramatic weight loss, often with strict rules, a short duration, or a single “magic” food. Examples include the cabbage soup diet, grapefruit diet, HCG diet, GM diet, 3 day diet, and 17 day diet. They are usually not sustainable and can be risky. We do not recommend them.
The HCG diet combines very low calories (often 500 kcal/day) with HCG (human chorionic gonadotropin), a hormone. HCG is not approved for weight loss and is illegal for that use in many countries. The diet is dangerous and can cause serious side effects. We do not recommend it.
The cabbage soup diet (or cabbage diet) is a short-term plan where you eat cabbage soup plus a few other foods each day. It is very low in calories and nutrients. Any weight lost is mostly water and is often regained. We do not recommend it. For lasting weight loss, use a balanced calorie deficit instead.
The GM diet (or GM diet plan) is a 7-day plan that assigns different food groups to each day (e.g. fruit only, vegetables only). It is very restrictive and low in protein and other nutrients. It is not sustainable and we do not recommend it. Sustainable weight loss comes from a balanced diet and calorie deficit.
The grapefruit diet claims grapefruit burns fat (it does not). The 3 day diet is an extreme short plan with very few calories. Both are fad diets that can cause nutrient deficiency and weight regain. We do not recommend them. See our weight loss diet and calorie deficit guides for a safer approach.
Many short-term or fad diets are not safe: they can be very low in calories and nutrients, cause fatigue, and lead to weight regain. Some (e.g. HCG diet) are dangerous. We do not recommend fad or short-term diets. For weight loss, talk to your doctor or dietitian and use a sustainable calorie deficit.
Summary
Fad diets and short-term diets (e.g. HCG diet, cabbage soup diet, cabbage diet, grapefruit diet, 3 day diet, 17 day diet, GM diet, GM diet plan, soup diet, cookie diet, egg diet, water diet, fruit diet, Scarsdale diet, oatmeal diet, salad diet, rice diet, chicken and rice diet, apple diet, meat and fruit diet) promise quick weight loss but are often unhealthy, unsustainable, and sometimes dangerous. We do not recommend them. For weight loss, use a sustainable calorie deficit and a balanced diet with the help of your doctor or dietitian. Use our calorie calculator, TDEE calculator, and weight loss diet and calorie deficit diet guides.
Use our calculators with this diet
Set your calorie target and plan meals with our free tools.
You might also like
Other diet guides that may fit your goals.
Weight loss diet
Balanced eating with a calorie deficit for sustainable weight loss.
Calorie deficit & low-calorie diet
Eating below maintenance calories for weight loss.
Cleanse & detox diet
Short-term plans claiming to detox. We do not recommend; body detoxes itself.
Blood type diet
Eat by blood type. Not supported by evidence; we do not recommend.
Sources and further reading
This article is for general education. For evidence on safe weight loss, see:
- Health authority guidance on fad diets and safe weight loss (e.g. NHS, NIH)
- Regulatory positions on HCG for weight loss (e.g. FDA)
Last updated: 20 February 2026. Content is for educational purposes only and does not replace medical advice. We do not recommend fad or short-term diets.