What Is a Keto Diet? Ketogenic Diet 101

what is a keto diet

The keto diet plan (ketogenic) is designed to switch the body from using sugars to ketones for fuel. Ketosis occurs when a person fasts (eats nothing at all), but that isn’t realistic. If the body receives lower amounts of carbohydrates from food, it switches to using fat from the body for fuel, and ketones are created in the liver. Additionally, if lower levels of carbohydrates are consumed, then there are lower levels of insulin; this helps increase fat to be used as fuel.

Who Should Not Be on a Low-Carbohydrate or Ketogenic Diet?

  • People who take insulin (close physician supervision required)
  • Women thinking of becoming pregnant
  • Women who are pregnant or breastfeeding
  • People with hypertension and on medication should check with their healthcare provider

What Is the Ketogenic Diet?

The definition of a ketogenic diet can vary for different people. Generally, the ketogenic diet requires people to eat less than 50 grams of carbohydrates for the body to reach a state of ketosis. For many people, this may require a carbohydrate intake of less than 20 grams per day. For everyone, the fewer amount of carbohydrates, the more effective the nutrition plan.

What Can you Eat on a Ketogenic Diet? Foods to Avoid

Foods full of sugar and starch, such as bread, pasta, rice, and potatoes, should be avoided. How many carbohydrates are in common foods?

  • Fruits: 7-20 grams
  • Potatoes: 15-20 grams
  • Cooked pasta: 25-30 grams per serving
  • Bread: as high as 45 grams per serving

Nutrition labels and programs like My Fitness Pal are helpful in recognizing the amount of carbohydrates in food.

What to Drink on a Ketogenic Diet?

Water is the ideal option, but unsweetened coffee and tea are fine. A 4-ounce glass of red wine is generally only two carbohydrates.

Benefits of the Ketogenic Diet

  • Weight loss: Insulin levels drop greatly, which allows for fat loss, generally without hunger. (More than 20 studies show that low-carbohydrate and ketogenic diets result in more effective weight loss.)
  • Improved energy and mental performance: Ketosis results in a steady flow of fuel to the brain. This may result in improved focus and concentration.
  • Control blood sugar: Ketosis lowers blood sugar levels.
  • Improved lipids and blood pressure: Ketosis lowers cholesterol, triglycerides, and hypertension and elevates HDL cholesterol levels

How to Know You’re in Ketosis

Physical symptoms of ketosis include dry mouth, increased thirst, increased urination, reduced hunger, and “keto breath” (a slightly fruity smell). Many tools to measure ketosis are available on the internet, such as urine strips, breath ketone analyzers, and blood ketone meters.

Potential Ketogenic Diet Side Effects

Reducing carbohydrates quickly may cause headaches, fatigue, dizziness, nausea, and irritability. For this reason, many people decrease their carbohydrate intake over several days to reach the level of carbohydrates required for ketosis. Symptoms usually subside quickly, and drinking fluids helps with overcoming these symptoms.


This article was written by Krishna Doniparthi, MD, FOMA, and Angela Golden, DNP, FNP-C, FAANP.