Is intermittent fasting good for weight loss?

Intermittent fasting is now a very popular eating pattern for weight loss. Unfortunately, most times, popular diets and eating patterns are recommended from non-experts and personal experience (1,2).

However, intermittent fasting is now a recognized eating pattern among scientific nutritionists, in fact, it has been adopted as a new therapeutic approach for obesity and reducing cardiovascular risks (1).

In this brief guide, we will answer the query “Is intermittent fasting good for weight loss?” We will cover relevant information like the types of intermittent fasting and their possible benefits; finally, we will present the potential drawbacks and considerations of intermittent fasting, as well as a comparison with other diets.

Is intermittent fasting good for weight loss?

Yes, intermittent fasting is good for weight loss. According to different studies, intermittent fasting can reduce your weight by around 2 – 13 % of your weight in a mean of 12 weeks (1,3).

Intermittent fasting is defined as “periods of eating alternated with period of not eating”. There are three types of intermittent fasting (1):

  • Alternate Day Fasting: this diet alternates one day of fasting and one day of eating. 
  • The 5:2 diet: this is a modification of Alternate Day Fasting, it involves 2 days of fasting per week and 5 days of eating.
  • Time Restricted Eating: this type of intermittent fasting is characterized by an eating window period during the day; for example, you are allowed to eat in a period of 4 to 10 hours daily followed by fasting the remaining hours of the day.

On the fasting days, people are allowed to eat approximately 500 calories, but the objective of fasting day is to just drink water or non-caloric beverages. On the other hand, the eating days are not restrictive on quantity and quality food (1).

How Does Intermittent Fasting Work for Weight Loss?

Intermittent fasting can help for weight loss because it induces your body to a negative calorie balance, and to use its reservoirs of energy during the fasting period (1,4).

The key for weight loss is to achieve a negative energy balance, in other words, your energy intake is lower than the energy you spend in all your activities (4). 

Moreover, all the nutrients you eat are stored either in glycogen (carbohydrates) or adipose tissue (fat) form. The intention of energy stores in your body is to have available energy when you don’t eat (4). 

Therefore, depriving your body of energy for a certain amount of time will force your metabolism to mobilize all energy stores. Mobilizing glycogen and fats will promote weight loss and changes in your corporal composition (such as fat mass reduction) (4).

What are the Potential Benefits of Intermittent Fasting?

The most desired benefit of intermittent fasting is weight loss; however, there is some evidence that intermittent fasting can help in the regulation of different processes in your body. For example, alternate day fasting and 5:2 diet can provide the following benefits (1,3):

  • A reduction of 5-11% of diastolic and systolic pressure in people with hypertension, or near to the threshold between normal and high blood pressure
  • Intermittent fasting can reduce between 10 and 20 % of LDL-cholesterol and total cholesterol in blood, without affecting HDL-cholesterol (also known as good cholesterol).
  • Intermittent fasting can help reduce glucose and insulin levels in blood, as well as improving insulin sensitivity.
  • A study demonstrated a reduction of 0.5 % on glycosylated hemoglobin, an important biomarker for diabetes diagnosis and management monitoring.

What are the Potential Health Risks of Intermittent Fasting for Weight Loss?

There is no much evidence in long-term studies to determine risks of intermittent fasting; however, here are some key points to take into account (1,3,5):

  • Intermittent fasting is not a restrictive diet for certain types of foods, so it is not likely to have a deficiency; however, you must ensure a complete diet on the eating days, for instance, including cereals and whole grains, lean meats, dairy products, fruits, and vegetables.
  • On fasting days it is critical to maintain a good hydration, and remember that you are allowed to eat a low-calorie meal or approximately 500 calories in your eating days.
  • This is a different eating pattern, so you might take a while to adjust to it, so don’t force yourself to a strict intermittent fasting from one day to the next one.
  • Do not engage in an intermittent fasting plan if you are pregnant or breastfeeding; if you are in one of those situations, you must eat the appropriate energy and nutrients daily to ensure a good nutrition for you and your baby.
  • There could be risks of hypoglycemia for people with diabetes and with glucose-control medication.

Finally, take into account that you should look for professional advice from a nutritionist specialist to do intermittent fasting.

How does intermittent fasting compare to other diets for weight loss?

According to different studies, there is slight or no difference between the weight loss with a calorie-restriction diet and intermittent fasting (1,3,6). 

The study of Jospe et al. (6) showed no difference among Intermittent fasting, mediterranean diet, and paleo diet in weight, waist circumference, and body fat mass. 

In summary, there is no best diet for weight loss, and all diets’ effects may vary from one person to another. So the best thing you can do is to look for professional advice from a nutritionist, then try different approaches to select the one that best fits you (2).


In this brief guide, we answered the query “Is intermittent fasting good for weight loss?” We covered relevant information like the types of intermittent fasting and their possible benefits; finally, we presented the potential drawbacks and considerations of intermittent fasting, as well as a comparison with other diets.


  1. Varady KA, Cienfuegos S, Ezpeleta M, Gabel K. Cardiometabolic benefits of intermittent fasting. Annu Rev Nutr, 2021;41(1):333–61.
  1. Freire R. Scientific evidence of diets for weight loss: Different macronutrient composition, intermittent fasting, and popular diets. Nutrition, 2020;69(110549):110549.
  1. Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, et al. Intermittent fasting and weight loss: Systematic review. Can Fam Physician, 2020;66(2):117–25.
  1. Joshi S, Mohan V. Pros & cons of some popular extreme weight-loss diets. Indian J Med Res. 2018;148(5):642-647.
  2. Joaquim L, Faria A, Loureiro H, Matafome P. Benefits, mechanisms, and risks of intermittent fasting in metabolic syndrome and type 2 diabetes. J Physiol Biochem, 2022;78(2):295–305.
  1. Jospe MR, Roy M, Brown RC, Haszard JJ, Meredith-Jones K, Fangupo LJ, et al. Intermittent fasting, Paleolithic, or Mediterranean diets in the real world: exploratory secondary analyses of a weight-loss trial that included choice of diet and exercise. Am J Clin Nutr, 2020;111(3):503–14.

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