Weight loss
Keto Diet Explained: Foods, Macros, Risks and a Sample Day
The ketogenic (keto) diet is a very low-carbohydrate, high-fat way of eating that pushes the body to burn fat and produce ketones for fuel. It can reduce appetite and help some people lose weight quickly, but it is restrictive and not suitable for everyone.
How keto works
When carbohydrate intake drops to roughly 20-50 g of net carbs per day, liver glycogen runs low and the body starts producing ketones from fat. This metabolic state is called ketosis. Most people reach it within 2-4 days.
Typical macro split
- Fat: about 70-75% of calories
- Protein: about 20-25%
- Carbohydrate: about 5-10% (20-50 g net carbs)
Net carbs are total carbohydrates minus fiber.
Foods to eat
Eggs, fish, poultry, meat, olive oil, avocado, nuts and seeds, cheese, butter, and non-starchy vegetables such as spinach, broccoli, zucchini, cauliflower and peppers.
Foods to avoid
Bread, pasta, rice, potatoes, most fruit (berries in small amounts are usually fine), sugar, sweetened drinks, beans and most processed snacks.
Side effects and risks
The first week often brings headache, fatigue, irritability and constipation, sometimes called the keto flu. Staying hydrated and increasing salt and magnesium intake can help. Longer-term concerns include nutrient gaps, higher LDL cholesterol in some people, and difficulty sticking to the diet.
Talk to a doctor first if you have type 1 or type 2 diabetes treated with medication, pancreatic, liver or kidney disease, or a history of eating disorders, or if you are pregnant or breastfeeding.
A sample day
- Breakfast: three-egg omelet with spinach and cheese.
- Lunch: chicken Caesar salad without croutons, extra olive oil.
- Dinner: pan-seared salmon, buttered broccoli and a side salad.
Frequently asked questions
How many carbs can I eat on keto?
Most people stay under 20-50 g of net carbs per day. Your exact limit depends on how your body responds.
Is keto safe long term?
Evidence on long-term safety is limited. Many people use it for months rather than years and then move to a less restrictive low-carb pattern.
Why am I not losing weight on keto?
Ketosis does not override energy balance. Calories from cheese, nuts and oils add up quickly, so check portions.
This article is for general education and is not medical advice. Speak with a doctor or registered dietitian before starting a new diet, particularly if you have a medical condition, take medication, are pregnant or breastfeeding.