8 Popular Diets That Can Backfire: Naturopath View (What to Eat Instead)

Written by Priti, Certified Naturopath (NDDY)  |  Published: November 2026

Quick answer

Keto, intermittent fasting, crash dieting, high-protein, gluten-free, oil-free, salt-free and paleo diets all work the same way: they remove something. That can be carbohydrates, meals, fat, salt, a food group or a protein limit. Some people feel fine for a while, but many end up tired, lose hair, or regain the weight. A safer way is to keep every food group, eat regular meals with some healthy fat, and lose weight slowly. If you have a medical condition, or your doctor has put you on a special diet, follow your doctor's plan and do not change it because of a trend.

"I did keto for six weeks, lost weight, and now I am tired, my hair is falling and my weight is back." Or, "I stopped oil and salt completely, so why do I feel worse?" After reading these lines, if you feel that it's you then you must read this article. Because following diet is good, but before adapting any diet you first understand the purpose of that diet.  

In this article I have explained five diets trends, that are popular. But before following them blindly, let's understand are they useful for you or not. 

The eight diets at a glance

Diet What it cuts or limits What can go wrong What I suggest instead
Keto Most carbohydrates (often 50 g a day or less) Tiredness and headaches at first; higher LDL cholesterol, kidney stones and nutrient gaps over time Smart carbs: millets, whole grains, pulses, fruit and vegetables
Intermittent fasting Eating hours (for example 16:8 or one meal a day) No clear weight-loss edge over normal meal timing in one trial; early heart-risk signal is still unproven; not for diabetes medicines, pregnancy or eating disorders A gentle 12-hour overnight gap and an early dinner
Crash diet Calories and meals Muscle loss, gallstones, hair fall, weight regain, disturbed periods Three regular meals, slow loss, movement and sleep
High-protein Often grains, fruit and fibre Constipation when fibre falls; should be avoided in kidney disease Protein at every meal, with dal, vegetables and whole grains
Gluten-free Wheat, barley, rye Can hide celiac disease if started before testing; packaged gluten-free foods may be low in fibre and nutrients Test first; if you need it, use ragi, jowar, bajra and rice
Oil-free All added fat Poor absorption of vitamins A, D, E, K and carotenoids; dry skin; constipation A small, measured amount of good oil or ghee, plus nuts and seeds
Salt-free All added salt Cramps and weakness if done without medical guidance; swapping to pink or rock salt may cut iodine Less salt (under 5 g a day), more potassium-rich foods, and iodised salt unless your doctor says otherwise
Paleo Grains, pulses, dairy Less fibre and calcium; for Indian eaters, no dal, roti or rice Seasonal vegetables with whole grains, dal and sprouts

1. Keto: not "zero carbs", and not for everyone

Keto was first developed as a medical diet for epilepsy, and doctors still use it that way, under supervision. As a weight loss trend, most keto plans limit carbohydrates to about 50 grams a day or less. That is not zero, but it removes most fruit, grains and pulses.

In the first days, many people get "keto flu": headache, tiredness, nausea, constipation, dizziness. Over the long term, higher LDL cholesterol, kidney stones, vitamin and mineral gaps and fatty liver have been reported, and researchers say we still know little about the very long term.

Please speak to your doctor first if you have thyroid, liver, pancreas or gallbladder problems (or had your gallbladder removed), or have ever had an eating disorder.

2. Intermittent fasting: popular, but the proof is thinner than the posts

Eating only in an 8-hour window (16:8), or one meal a day, is everywhere on social media. Two pieces of research are worth knowing:

  • A 12-week randomised trial of 116 adults compared 16:8 eating with normal meal timing. The fasting group lost about 0.94 kg and the other group about 0.68 kg. That small gap was not statistically significant, so fasting alone was no better for weight loss.
  • A 2024 conference abstract from the American Heart Association followed more than 20,000 US adults and found that people eating within less than 8 hours a day had a 91 percent higher risk of dying from heart disease. This is an early, observational finding based on two days of self-reported food. It is not peer reviewed and cannot prove cause, so please see it as a question that needs more research, not a verdict.

My practical view: the gentle version works for many people, a 12-hour overnight gap and an early, light dinner. Strict one-meal-a-day plans are where I see tiredness, hair fall and binge eating. Do not fast if you take diabetes medicine, are pregnant, breastfeeding, underweight, a teenager, or have had an eating disorder. If your periods change, stop and speak to your doctor.

3. Crash dieting: the gallstone fact nobody tells you

Soup-only days, one fruit meal, 800 calories: it gives a fast number on the scale. Here is what the research adds:

  • Gallstones. Losing 3 pounds (about 1.4 kg) or more a week raises gallstone risk. In people on very-low-calorie diets, up to 25 percent develop gallstones. Repeated loss and regain raises the risk further.
  • Muscle. Without protein and strength work, a very-low-calorie diet can cost more than a quarter of your lean body mass. Less muscle means a slower metabolism.
  • Regain. In one very-low-calorie diet study, 40 percent of people regained more than they lost.
  • Hair, energy and periods. Hair fall, weakness, constipation and low blood sugar are common. In women, very low intake may disturb the menstrual cycle.

In Ayurveda, we say skipping meals weakens agni, your digestive strength. You do not need that theory to see it: an underfed body protects itself by slowing down.

4. High-protein diets: what "high" really means

Protein is not the enemy. Muscle needs it, and many people eat too little. The question is how far to go. Researchers usually call more than 1.5 g of protein per kg of body weight a day "high", compared with about 0.8 g per kg in standard advice. For a 60 kg woman, that is above 90 g a day.

  • Kidneys. A 2018 review of 1,358 healthy adults found that about 1.8 g per kg for up to two years did not worsen kidney function. But those studies were small and not ideal, and some observational studies link a lot of animal protein to a higher risk of kidney disease. If you have kidney disease or diabetes, high-protein diets are generally avoided. Ask your doctor for your number.
  • Fibre. When protein shakes and meat replace roti, fruit and vegetables, fibre falls and constipation follows.

I suggest protein at every meal from dal, sprouts, curd, paneer, eggs or fish, always with vegetables and a whole grain.

5. Gluten-free: test before you cut

Gluten-free is essential for people with celiac disease, and also for people who have a confirmed gluten sensitivity. For everyone else, nothing shows that it helps with weight loss or other conditions.

Did you know? If you suspect celiac disease, ask for the test before you stop eating gluten. The blood test works while you are still eating it. If you stop first, antibody levels can fall within months and the test becomes less accurate, which can delay a diagnosis for years.

Also check labels. Packaged gluten-free breads and biscuits can differ in fibre, fat, sodium and added nutrients compared with the ordinary version. If you do need gluten-free, the Indian kitchen has an advantage: ragi, jowar, bajra and rice (look for certified gluten-free products if you are celiac).

6. Oil-free: your salad may be wasted

Oil-free sounds heart-healthy, but fat does a job nothing else can. Vitamins A, D, E and K need fat to be absorbed. Here is the fact I like to share:

Did you know? In a study at Iowa State University, people ate salads of spinach, lettuce, tomatoes and carrots with dressing containing 0, 6 or 28 grams of oil. With fat-free dressing, almost no beta-carotene was absorbed. The more oil, the more carotenoids reached the blood. So a plain "healthy" oil-free salad can waste much of the colour in your vegetables.

A small amount of oil with your vegetables, such as a teaspoon of olive or sesame oil on the salad, makes the vegetables work for you. Nuts, seeds and ghee in small amounts do the same.

Two cautions. If a cardiologist has put you on a very low-fat programme, follow it. And if you live in the US, note that the FDA treats expressed mustard oil as a possible unsafe food additive because of its erucic acid, so it is often sold there for external use only. Choose olive, sesame, groundnut or ghee in small amounts instead.

7. Salt-free: the pink salt myth

People who avoid salt often switch to rock salt (sendha namak) or pink Himalayan salt, thinking it is mineral-rich and safe. In fact:

  • Pink salt is up to about 98 percent sodium chloride, the same as table salt. The other 2 percent holds tiny amounts of potassium, magnesium and calcium, too small to make a measurable health difference. It does not lower your sodium.
  • It likely contains less iodine than iodised salt. This matters if you have a thyroid problem or live where iodine is low. If you switch, make sure iodine comes from elsewhere, such as dairy, fish or iodised salt in your cooking.
  • The blood pressure fix is two-sided. The World Health Organization advises under 5 g of salt and at least 3,510 mg of potassium a day. Most of us eat too much salt and too little potassium. Fruit, vegetables, pulses and nuts supply potassium, so this is one more reason not to cut food groups.

Some people are told by their doctor to follow a strict low-salt diet, for heart, kidney or blood pressure reasons. If that is you, follow your doctor's number exactly. What I do not recommend is deciding by yourself to go to zero.

8. Paleo: great vegetables, missing dal

Paleo encourages whole foods, which is good. But it removes grains, pulses and dairy altogether. For anyone who grew up on dal, roti, rice and curd, that means removing the main sources of fibre, plant protein and calcium. The long-term evidence on strict Paleo is also limited.

My advice: keep the idea of eating real food, and keep the food groups. Millets, whole grains, lentils, sprouts and seasonal vegetables cover what Paleo takes away.

Is your diet "extreme"? Four quick questions

  • Does it ask you to cut a whole food group?
  • Could you follow it for the rest of your life, including at a family wedding?
  • Do you feel tired, cold, moody or constipated on it?
  • Does it promise results in a few days?

If you answered yes to any one of these, take it as a sign to slow down and speak to a professional. When you keep switching between diets, your body never gets a steady rhythm to work with.

What I ask clients to do instead

  • Build a balanced plate: half vegetables, a quarter whole grain or millet, a quarter dal, sprouts, paneer or eggs, with a little healthy fat.
  • Eat regular meals, with the biggest at midday, and finish dinner early. 
  • Lose weight slowly, by walking, strength or yoga, and sleep. A steady half to one kilo a week is plenty.
  • Check hormones and gut first if weight will not move. My guides on hormonal imbalance in women and improving gut health are a good place to begin.

Read next

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These products are not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, nursing, or taking medicine, please speak to your doctor before use.

Please be careful if

  • You have high blood pressure, heart, kidney or liver disease, or diabetes. Do not change your salt, fat, protein or carbohydrate intake, fast, or stop medicine, without your doctor.
  • You have a thyroid condition. Check your iodine sources before changing your salt.
  • You are pregnant, breastfeeding, underweight, a teenager, or have had an eating disorder. Do not diet or fast without medical guidance.
  • You think you may have celiac disease. Get tested before you stop gluten.
  • You take regular medicine. Ask your pharmacist before adding any herb or tea.

When to see a doctor

Please see a doctor if you have severe or lasting pain in the upper right belly (especially after fatty meals), yellow skin or eyes, dizziness or fainting, an irregular heartbeat, missed periods for three months, heavy hair fall, constant tiredness, long-lasting diarrhoea or bloating after wheat, or you cannot stop thinking about food or weight. Do not change a diet your doctor has prescribed.

Frequently asked questions

Which diet is safest for long-term weight loss?

One that includes all food groups: whole grains, vegetables, fruit, pulses, healthy fats and moderate protein, with daily movement and enough sleep. Aim for slow, steady loss of about half to one kilo a week.

Is intermittent fasting bad for you?

It is not harmful for everyone, but it is not proven to beat normal meal timing for weight loss. An early finding linked very short eating windows to heart risk, though it is preliminary. Avoid it if you take diabetes medicine, are pregnant or underweight, or have had an eating disorder.

Is a high-protein diet bad for your kidneys?

In healthy adults, studies of up to two years have not shown kidney harm, but the evidence is limited. If you have kidney disease or diabetes, high-protein diets are generally avoided, so ask your doctor first.

Should I go gluten-free to lose weight?

There is no proof that it helps weight loss. If you suspect celiac disease, ask for testing before stopping gluten.

Is the keto diet bad for you?

It is used medically for epilepsy. As a weight-loss diet it can cause tiredness, constipation, higher LDL cholesterol, kidney stones and nutrient gaps. Talk to your doctor first if you have thyroid, liver, pancreas or gallbladder problems.

Why do I regain weight after a crash diet?

Severe restriction slows your metabolism and costs muscle. When you eat normally again, you regain faster. In one very-low-calorie diet study, 40 percent of people regained more than they lost.

Is pink Himalayan salt better than table salt?

No. It is up to about 98 percent sodium chloride, like table salt, and the trace minerals are too small to matter. It also likely has less iodine than iodised salt.

Do I need oil in my diet?

Yes, a small amount. Vitamins A, D, E and K and carotenoids need fat to be absorbed. A teaspoon or two per meal is usually enough, but follow your doctor's advice if you have a heart condition.

Sources and further reading

Priti Gupta, Certified Naturopath (NDDY), 8+ years of experience in Ayurveda and natural healing, Founder of Yipisale

This article is for educational purposes and is not a substitute for medical advice. If you have a medical condition, are pregnant, or take medicine, please speak to your doctor before changing your diet.

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