The 5 Diets Most People Try, and What Happens With Each

By the Strength from the Well Editorial Team · Evidence last reviewed September 2026 · Not reviewed by a licensed clinician (why we say that)

The short answer

The five approaches most people try are keto, intermittent fasting, low fat or calorie counting, the Mediterranean pattern, and high protein eating. In trials lasting a year or more they produce broadly similar average weight loss, because each one reduces intake in a different way, but they differ a lot in who finds them livable and in what else they do for health. The Mediterranean pattern has the strongest evidence for cardiovascular outcomes; the rest are mostly judged on weight and on whether a person can keep going.

Key points

Over twelve months, average weight loss across these approaches lands in a similar range. The differences between individuals are far larger than the differences between diets.
Fast early results on keto and fasting are partly water weight, which makes the later slowdown feel worse than it is.
The Mediterranean pattern is the only one of the five with large trial evidence for cardiovascular events, not just for weight.
High protein eating is less a diet than a modifier you can add to any of the others, and it is the one most consistently linked to preserving muscle.
Nearly every one of these fails for the same reason: it collides with real life, not with metabolism.
Anyone on diabetes or blood pressure medication should talk to a prescriber before a major change, because these diets can change how those medications behave.

Before the list: what these five have in common

Each of these approaches works, when it works, by getting a person to take in less energy than they use. They just take different routes. Keto removes an entire macronutrient and with it most convenience food. Fasting removes hours of the day. Calorie counting makes intake explicit. The Mediterranean pattern shifts meals toward foods that are filling per calorie. High protein eating changes hunger directly.

Because they end up in the same place, comparing them on average weight loss produces boring results. The interesting differences are elsewhere: what they do to your bloodwork, what they cost, and how they behave at a wedding or on a night shift.

1. Keto and low carbohydrate

What it is: carbohydrate restricted far enough, usually to a small fraction of daily intake, that the body shifts toward producing ketones from fat for fuel. Less strict low carbohydrate eating stops short of that but follows the same logic.

What the evidence says: early weight loss is fast, faster than on other diets, but a large part of the first week or two is water released as the body uses up stored glycogen. At six months keto often leads. By twelve months the gap with other diets typically narrows to nothing meaningful in controlled trials. Triglycerides usually fall and HDL usually rises. LDL cholesterol is unpredictable: it falls for some people and rises substantially for others, which is worth knowing and worth checking rather than assuming.

Who tends to do well: people who find protein and fat genuinely filling, people whose eating problem is grazing and snacking rather than portion size at meals, and often people with insulin resistance or type 2 diabetes, who sometimes see blood sugar improve quickly. That last group needs medical supervision, because diabetes medication frequently has to be adjusted when carbohydrate drops.

Why people quit: the social cost, mostly. Keto is difficult at restaurants, at other people's houses and on trips. The first two weeks often bring fatigue, headache and irritability. And a normal meal out does not just add calories, it visibly reverses the water weight, which many people read as total failure.

2. Intermittent fasting

What it is: an eating schedule rather than a food list. The common versions are time restricted eating, where all food happens within a window of perhaps eight or ten hours, and intermittent approaches with one or two very low intake days a week.

What the evidence says: it reliably produces weight loss, and in most controlled trials it produces about the same weight loss as continuous calorie restriction. When randomized trials have compared a time restricted window to the same daily calories eaten across three normal meals, the difference in weight lost has generally been small. One trial of a sixteen hour fasting window found not only minimal extra weight loss but a notable share of the weight lost coming from lean mass, which is a reason to pair fasting with protein and resistance training if you use it. Claims about metabolic benefits independent of weight loss are, so far, not firmly established in humans.

Who tends to do well: people who like rules better than arithmetic, people who are not hungry in the morning anyway, and people whose main problem is evening eating. It is genuinely simpler than counting.

Why people quit: shift work and family schedules break it. Some people become intensely hungry and then overeat inside the window. And for anyone with a history of restriction and bingeing, fasting can reawaken that pattern, which is a real risk. People with diabetes on insulin or sulfonylureas should not adopt fasting without a prescriber involved, because of hypoglycemia risk.

3. Low fat and calorie counting

What it is: the oldest mainstream approach, and still the one used in most clinical weight programs. Either fat is limited, or total intake is tracked against a target, or both.

What the evidence says: this is the best studied of the five, because it is what large trials have used for decades. Structured calorie reduction with support produces roughly 5 to 10 percent weight loss in the first six to twelve months. Large lifestyle trials in people at risk for diabetes have shown that this magnitude of loss reduces progression to type 2 diabetes. Head to head, it performs about as well as low carbohydrate eating at a year.

Who tends to do well: people who find data motivating rather than oppressive, people who want no food to be off limits, and people who respond well to structure and feedback. Modern tracking apps have made it considerably less tedious than it once was.

Why people quit: it demands continuous attention, and counting also tends to drift into inaccuracy over time in a predictable direction. For a subset of people, quantifying every bite makes eating anxious in a way that does lasting damage. If tracking makes you feel worse about food rather than more informed, stop tracking.

4. The Mediterranean pattern

What it is: not a weight loss diet in origin, but a description of how people ate in parts of southern Europe. Vegetables, fruit, legumes, whole grains, fish, nuts, olive oil as the main fat, modest dairy, little red and processed meat.

What the evidence says: this is the only one of the five with large randomized evidence for hard cardiovascular outcomes rather than just weight. A major Spanish trial found fewer major cardiovascular events in people assigned to a Mediterranean pattern supplemented with olive oil or nuts than in a control group. That trial was retracted and republished in 2018 after problems with randomization at some sites, and the main conclusion survived the reanalysis, though it is best described as reduced events in a high risk population rather than a precise number. For weight specifically it produces moderate loss, usually less dramatic than keto in the first months.

Who tends to do well: people who cook, people who do not want to eliminate any food group, and people whose main concern is heart health and long term risk rather than a number on the scale by summer.

Why people quit: it is often not dramatic enough to feel like it is working, since weight comes off slowly. Fish, nuts and good olive oil are expensive. And because it has no rules, only tendencies, it is easy to drift back to how you ate before without noticing.

5. High protein eating

What it is: raising protein substantially above the minimum requirement, often toward a quarter to a third of daily intake, usually while reducing refined carbohydrate. It is frequently combined with one of the other four rather than done alone.

What the evidence says: protein is the most satiating of the three macronutrients, and trials that raise protein during weight loss tend to find better appetite control and better preservation of lean mass. That second point matters, because some of any weight lost is muscle, and losing muscle lowers resting energy use and reduces strength over time. Higher protein plus resistance training is the best documented combination for shifting the ratio toward fat.

Who tends to do well: nearly everyone losing weight benefits from more protein than they are used to, but especially people over fifty, people who have lost and regained weight several times, and people using a GLP-1 medication, where intake drops sharply and muscle loss is a genuine concern.

Why people quit: planning. Protein requires cooking and forethought in a way that carbohydrate does not. It can also get monotonous and expensive. People with reduced kidney function should ask their clinician before raising protein substantially; for people with healthy kidneys, the old warning about protein causing kidney damage has not held up.

So which one should you pick

The honest answer is that the evidence does not pick for you. What it says is that the difference between these diets is small and the difference between doing one and doing none is large, so the right one is the one whose demands match the shape of your life.

A rough guide: if your problem is constant snacking, keto or high protein tends to help most. If your problem is late night eating, a time restricted window is a direct fix. If you want data and flexibility, count. If you mostly want to be healthier and are not in a hurry, the Mediterranean pattern has the best outcome evidence. Whichever you pick, adding protein and resistance training improves all of them.

And if you have tried three of these and they all fell apart, that is closer to the norm than the exception. It is worth considering that the obstacle may be sleep, stress, medication or an untreated condition rather than the fourth diet.

Common questions

Which diet loses the most weight in the first month?

Usually keto, but a good portion of the early difference is water. Cutting carbohydrate depletes stored glycogen, and each gram of glycogen holds several grams of water with it. The fat loss rates converge over the following months, so early scale movement is a poor predictor of where you end up.

Can I combine these?

Yes, and most people effectively do. A Mediterranean pattern with more protein, or a time restricted window with attention to portions, are reasonable combinations. The main caution is stacking so many restrictions at once that the plan becomes impossible to follow on an ordinary Tuesday.

Do any of these work better for people with type 2 diabetes?

Lower carbohydrate approaches often improve blood sugar quickly, and the Mediterranean pattern has good evidence in this population too. The important point is medical: if you take insulin or a sulfonylurea, sharply reducing carbohydrate or adding fasting can cause dangerously low blood sugar unless medication is adjusted. That has to happen with your prescriber.

Why do I regain the weight regardless of which one I used?

Because regain is driven less by the method than by what the body does after weight loss: resting energy use falls and hunger signaling rises, and both persist well past the end of the diet. That is why a maintenance plan matters at least as much as the diet, and why ongoing support changes outcomes more than switching methods does.

Sources

This is information, not medical advice. Strength from the Well is an independent publisher. Nothing here is a diagnosis, a prescription, or a recommendation to start or stop any treatment. Talk to a clinician who knows your history before you act on anything you read here — including anything you read here that contradicts them.