Keto, high-protein or low carb

All three cut out bread, pasta and sugar, which is why people often mix them up. What separates them is what takes the place of the carbohydrates: keto puts fat there, the high-protein diet protein. Low carb does not cut carbs as hard, so it has no need to replace them with anything in particular.

The figures in the examples come from the food database. For the basics of keto there is the guide The keto diet for beginners.

The three diets at a glance

Keto

Carbohydrates drop so low that the body switches to fat as its main fuel and makes ketones. Most of the calories come from olive oil, eggs, cheese, oily fish, meat and nuts; protein stays moderate.

The hard part is the first week, until the body gets used to the new fuel. After that the plate, with its fat and protein, is quite filling.

High-protein

The high-protein diet, as it is known in Greece, cuts fat along with the carbohydrates. What is left on the plate is lean meat, fish, egg whites, fat-free dairy and vegetables.

With both fat and carbs missing, calories drop a lot and at first the weight comes off fast. It is the strictest of the three, though; anyone who has tried to keep it up for months knows that.

Low carb

Low carb is the most relaxed of the three and has no single definition. Most people mean under 130 grams of carbohydrate a day, which leaves room for a piece of fruit, some pulses or a small potato. With that many carbs, ketosis does not usually happen.

It suits people who want to cut down on carbs without weighing everything.

One lunch, three ways

Take the same dish: chicken with a salad of lettuce and cucumber (100 g of each). From one diet to the next the cut of chicken, the oil and the side change. Look how much the figures change with them:

On keto, fat provides about two thirds of the calories on the plate. On the high-protein diet protein takes that share, with the calories falling to almost half. On low carb, 27 of the 32 grams of carbs come from the potato.

What the studies say

For weight loss the differences turn out smaller than you might expect. In the DIETFITS study, 609 adults followed either a low-fat or a low-carbohydrate diet for a year; at 12 months the first group had lost 5.3 kg and the second 6.0 kg, a difference that was not significant.

On protein, the European Food Safety Authority (EFSA) estimates that 0.83 grams per kilo of body weight a day is enough for almost all adults. For someone weighing 80 kilos that comes to about 66 grams, close to what the high-protein lunch above has on its own.

Which one to choose

If you want ketosis and you like eggs, cheese and olive oil, keto is the natural fit. If you do not want to give up fruit and pulses completely, low carb will suit you better. The high-protein diet is for a short stretch, since over months it is the hardest to keep up.

You can perfectly well start with low carb and move to keto once you are used to it. The Macro calculator works out your own amounts, and the Most protein list has protein-rich foods.

Frequently asked questions

Is keto a high-protein diet?

No. On keto protein stays moderate and fat provides most of the calories. Cut the fat and raise the protein and you have arrived at the high-protein diet.

Which one helps you lose the most weight?

Studies find small differences. You lose more with the one you can stick to for longer.

Can I eat fruit on low carb?

Yes, in small portions. A 180-gram apple has about 20 grams of net carbs, which fit easily within 130.