What is fat fasting and is it good for weight loss?

photo of vegetable salad in bowls

Fat fasting actually involves eating more fat, not limiting its intake.

Between all the trendy diets like carbs, keto and occasional fasting, it can be hard to keep track of and figure out what might actually work for you.

Moreover, the abundance of these diets has led to all sorts of twists and other versions, including this one: fasting fat.

Although the name sounds a bit contradictory, this diet involves increasing fat intake, but only for a short time.

What is fat fasting and how to implement it?

Fat fasting, a short-term low-carb meal plan that usually lasts only three to five days, said New Jersey dietitian Erin Palinski-Wade, RD, CDE, author of the Belly Fat Diet For Dummies. “Although this is not actual ‘fasting’, it is called one because the body is forced into a state of ketosis (when you burn fat for energy) due to fat intake, a low carbohydrate content,” explains Paliński-Wade.

While it sounds a bit like a fast keto diet, it’s not exactly the same thing. Unlike a keto diet, calories are limited to 1,000 to 1,200 a day, and 80 to 90 percent comes from fat, which is a little more fat and significantly fewer calories compared to a standard keto diet. But it is similar in that the focus is on increasing fat intake to achieve ketosis.

Does it really help burn fat?

Yes, it helps. However, not every fat loss is likely to be sustainable. As mentioned, fat quickly forces the body into ketosis, which is the process your body uses to convert fat into energy when the body starves glucose, explains Palinski-Wade. Your body no longer uses glucose (which is produced from carbohydrates) for fuel when you are fasting or when carbohydrate intake is very low, she adds.

“Very low carbohydrate content and low calorie fat levels quickly drive the body into ketosis,” explains Palinski-Wade. The method has been touted as a way to break through the plateaus for weight loss or for individuals on a ketogenic diet to return to a state of ketosis after a ‘day of cheating’, ”she notes.

What to eat and what to avoid on this diet?

Remember: The goal is to keep calories between 1,000 to 1,200 a day and consume 80 to 90 percent of total calories from fat.

Thus, foods high in fat with little or no carbohydrates are an ideal choice for this diet, says Palinski-Wade. There may be animal and plant foods, such as:

  • High fat walnuts
  • avocado
  • oil
  • Chicken
  • eggs
  • Meat with a high fat content (ie bacon)
  • Butter
  • Cream
  • Non-starchy vegetables (for example, zucchini and spinach) cooked in oil
  • Calorie-free drinks (water, tea, coffee, seltzer)

Foods you would like to avoid during fasting fats include:

  • Processed, packaged food (think: cereals, cookies, white bread)
  • Sugar drinks
  • Low fat meat (ie chicken)
  • Fish
  • Most fruits
  • Low fat milk
  • Beans

Is fat fasting healthy and safe?

Due to the extremely low calorie intake and very limited choice of meal plan, it would be impossible to meet your daily nutritional goals while pursuing fast fats, says Palinski-Wade.

“This plan is promoted to just three to five days as a quick start to losing weight or burning fat, but restrictive diets like these are unsustainable in the long run and mostly result in bloating after such periods of restriction,” she explains. “Very low calorie and carbohydrate intake with this post can result in decreased energy, mood swings, decreased endurance, and nausea and headaches.”

For people with diabetes or those taking blood glucose-lowering medications, this type of meal can also significantly increase the risk of hypoglycemia, he adds. This form of fasting can also negatively affect athletes and those with an intense exercise routine.

Also read: Side effects of the keto diet

Who is fat fasting suitable for?

Palinski-Wade notes that she would generally not recommend this diet to anyone. However, if someone tries this diet plan, they should be sure to discontinue it within three to five days to prevent nutrient deficiencies, he adds.

“In general, a diet system crash“ like this plan results in reversible behaviors in diets, yo-yo diets, and unsustainable weight loss, ”she says. “People with diabetes should definitely avoid this form of diet (or consult with their medical team before starting) to prevent hypoglycemia.”


Fasting fat can help you burn fat or temporarily slip through the plateau for weight loss, but weight loss is unlikely to be sustainable and can lead to dietary deficiencies – and Palinski-Wade does not recommend this technique.