Weight Loss & Metabolic Health
What Is the Keto Diet?
Last reviewed: May 2026 · Haute MD Editorial Team
The ketogenic (keto) diet is a very low-carbohydrate (typically under 50 g/day), moderate-protein, high-fat eating pattern that depletes glycogen and shifts the body into nutritional ketosis, where fat-derived ketones become the primary fuel. It can be highly effective for weight loss, type 2 diabetes, and seizure disorders, but is restrictive and not appropriate for everyone.
How ketosis works
Restricting carbohydrates to under 50 grams per day for several days depletes liver and muscle glycogen. The liver then converts fatty acids into ketone bodies (beta-hydroxybutyrate, acetoacetate, acetone) that fuel the brain and muscles in place of glucose. Insulin levels fall dramatically, which promotes fat mobilization and oxidation. Most people enter nutritional ketosis within 3–7 days of strict carbohydrate restriction.
Weight loss and metabolic effects
Keto often produces rapid initial weight loss — much of the first week is glycogen and water — and steady fat loss thereafter, in part because high-fat, high-protein meals are very satiating. It is particularly useful for patients with type 2 diabetes, insulin resistance, PCOS, and metabolic syndrome, often reducing or eliminating glucose-lowering medications under medical supervision. It is not superior to other diets long-term once calories are matched, but adherence may be easier for some.
Who should avoid keto and how to do it safely
Keto is generally not recommended for pregnant or lactating women, patients with pancreatitis or significant kidney disease, those with eating disorder history, or athletes in primarily glycolytic sports. Common side effects — 'keto flu,' constipation, electrolyte imbalance — are managed with adequate sodium, magnesium, potassium, and fluids. Long-term sustainability is the biggest limitation: most patients move to a less restrictive low-carb pattern after the initial fat-loss phase, with physician monitoring of lipids, kidney function, and micronutrient status.
Frequently Asked Questions
How fast does keto produce weight loss?
First-week loss of 5–10 pounds is common and largely water/glycogen. Sustained fat loss of 1–2 pounds per week is typical thereafter.
Is keto safe for the heart?
It can be when built around minimally processed fats, fatty fish, nuts, olive oil, and non-starchy vegetables. A version heavy in processed meats and saturated fat can worsen lipids in susceptible patients — physician monitoring is wise.
What is the difference between keto and low-carb?
Keto restricts carbs to under ~50 g/day to produce ketosis; low-carb generally means under 100–150 g/day without requiring ketosis. Low-carb is easier to sustain for most people.
Can I do keto on a GLP-1 medication?
Yes, but protein priority becomes even more important due to reduced appetite. Coordinate with your prescribing physician to monitor electrolytes and avoid undereating.
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