Nutrition

Ketogenic (Keto) Diet: A Complete, Honest 2026 Guide

The keto diet is neither a miracle nor poison: it is one more tool that works for some people and goals, not for everyone.

By the TrainerStudio team | Published May 26, 2026

What it is and how ketosis works

The ketogenic diet drastically reduces carbohydrates (usually below 50 g/day) and increases fat. When glucose is scarce, the liver produces ketone bodies that the body uses as fuel: that state is called ketosis.

It is neither new nor magic. Its main effect on weight is largely explained by reduced appetite and the removal of many ultra-processed foods, which makes a calorie deficit easier.

What to eat and what to avoid

The key is to prioritize quality fats and proteins and limit carbohydrates as much as possible. It is a restrictive diet, so variety and planning matter a lot.

Yes

Eggs, oily fish, meat, avocado, olive oil, nuts and low-carb vegetables.

In moderation

Full-fat dairy and some fruit such as berries.

Avoid

Bread, pasta, rice, sugar, legumes and most fruit.

Benefits, risks and who it suits

It can help lose weight, control appetite and, in specific clinical contexts (epilepsy, certain metabolic cases), it has therapeutic use. Some people report more satiety and stable energy.

But it is not for everyone. It can reduce performance in high-intensity sports, causes the so-called keto flu at first, complicates social life and is hard to maintain long term. It is not advised without supervision during pregnancy, certain disorders or for strength-speed athletes. The best diet is still the one a person can sustain.

How TrainerStudio helps

If a client wants to try keto, in TrainerStudio you can leave clear guidelines, resources on allowed foods and a check-in to monitor energy, performance and adherence from the start.

That avoids blind trial and error: you review real data and decide whether to keep, adjust or change the approach based on how the person responds.

Follow up on your clients' diet

With TrainerStudio you can assign guidelines, log adherence and review results to decide with data whether a diet like keto fits the client.