Written on February 3, 2023 by Amy Harris, MS, RN, CNM. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Keto, intermittent fasting, paleo, warrior...what diet will be in the spotlight next? While all of these options keep the diet industry in business, they rarely answer the one question we all have: Which diet plan will help me lose weight and keep it off?
You are not alone in asking this question. Unfortunately, there is not one easy answer because everyone’s body is different. Everlywell’s new weight management telehealth service is committed to finding that healthy weight for every body, even yours. In this post, we’ll help you understand the pros and cons of two approaches to weight loss: keto vs. intermittent fasting.
The biggest difference between keto and intermittent fasting is that intermittent fasting diets tell you when you can eat, whereas keto diets tell you what and how much you can eat.
“Keto” is short for ketogenic, which describes when your body uses fat as its primary fuel source instead of carbohydrates (carbs). The keto diet is an extreme form of a low-carb diet, limiting you to less than 20-50 grams of carbohydrates per day (for reference, one bagel has approximately 25 grams of carbs) .
When you follow a ketogenic diet, you replace the calories you usually eat in carbohydrates (bread, pasta, potatoes, sugar) with calories from proteins and fats such as fatty cuts of meat, processed meats, lard, and butter.
In contrast, intermittent fasting is an eating pattern that includes hours or days with no or minimal food consumption (called fasting) interspersed with hours or days when you eat a regular diet . It does not involve cutting out carbohydrates and, in fact, lets you eat your normal diet at non-fasting times.
Many people choose the keto diet as a “quick fix” diet — a way to quickly drop some weight, but not as a major life change. What is appealing about keto diets is that:
Research shows people tend to lose weight following a keto diet within two to three weeks, whereas it can take a month or more to see any weight change with intermittent fasting [1,4].
Healthcare providers, nutritionists, and researchers have serious concerns about the long-term risks of following the keto diet beyond six months . Not enough long-term research studies have followed humans on ketogenic diets for years at a time, although animal studies do indicate reduced disease risks and health benefits . In the short term, some of the problems with the keto diet are:
Research studies have shown that repeated fluctuations in weight (as might happen if you repeatedly stop and start the keto diet) result in a steady increase in body weight over time. They can also increase your risk for high blood pressure, gallbladder disease, and high cholesterol .
Intermittent fasting is not new on the diet scene and is popular among dieters and healthcare professionals because it:
A systematic review of 40 studies found that intermittent fasting was effective for weight loss, with a typical loss of 7-11 pounds over 10 weeks .
Fasting, even for a couple of hours, is not for everyone. Other reasons why people say no to intermittent fasting as a method of weight control are:
Finding yourself confused by these lists of pros and cons and not sure which weight control plan is right for you?
When comparing keto vs. intermittent fasting, keep in mind that, in the short term, people tend to lose more weight quicker. That initial success can come at a high price, however, with more unpleasant side effects, potential health risks, and a greater likelihood of harmful weight cycling.
Over months and years, however, more people can successfully maintain a meaningful weight loss (5-10 percent of their original body weight) for more than a year following intermittent fasting plans . The variety of intermittent fasting plans, their flexibility, and their lack of prohibiting entire food groups make them more attractive and feasible than keto diets. However, more research and time are necessary to confirm the long-term safety of intermittent fasting diet plans .
When to stop a keto diet: what to know
How long should you do intermittent fasting?