The Keto Diet Explained: A Beginner's Guide
The ketogenic, or keto, diet is a very low-carbohydrate, high-fat way of eating. By cutting carbs to a small share of your calories, the diet pushes your body to burn fat for fuel and produce molecules called ketones — a state known as ketosis. It has become popular for weight loss, but it is a significant change to how you eat and is not the right fit for everyone.
How keto works
Normally your body runs mainly on glucose from carbohydrates. On keto, carbs typically drop to around 5 to 10% of calories — often under 20 to 50 grams a day — while fat rises to roughly 70%. With little glucose coming in, the liver converts fat into ketones, which most tissues, including the brain, can use for energy. Reaching ketosis usually takes a few days to a week.
What you eat on keto
- Plenty of: meat, fish, eggs, cheese, nuts, seeds, oils, avocado, and low-carb vegetables.
- Limited or avoided: bread, rice, pasta, potatoes, most fruit, sugar, and starchy foods.
- Protein is moderate, not unlimited — too much can blunt ketosis, too little costs you muscle.
The honest pros and cons
Many people lose weight on keto, partly because it is filling and partly because cutting a whole food group reduces overall calories. Some report steadier energy and appetite. On the other hand, the first week can bring the keto flu — fatigue and headaches as your body adapts — and the diet is restrictive, can be low in fibre, and is hard for many people to sustain long term. As with any diet, weight loss still comes down to a calorie deficit overall.
Is keto better than other diets for weight loss?
Research generally finds that, calorie for calorie, keto is about as effective as other approaches over the long run. Its advantage is appetite control for some people; its disadvantage is how restrictive it is. The best diet is the one you can actually maintain.
Who should be cautious?
Anyone with diabetes, kidney or liver conditions, who is pregnant, or who takes medication should speak to a doctor first, as keto can interact with medication and health conditions. It is also a poor fit for anyone with a history of disordered eating.
The bottom line
Keto is a very low-carb, high-fat diet that shifts your body to burning fat for fuel. It can work for weight loss and appetite control, but it is restrictive, has an adjustment period, and is not for everyone. If you try it, plan your macros, prioritise food quality, and check with a professional first. Use our free macro calculator to set realistic targets.