Main differences between diet and fasting

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In an attempt to lose weight, many people slip into the extremes of fasting. However, it is mostly because of misunderstanding and not distinguishing the difference between diet and fasting. To help you healthily lose weight without jeopardizing your overall health, this detailed article is on identifying the difference between these two eating regimes and their impacts on the human body and weight.

Both dieting and fasting consider certain eating regimes that by reducing calorie intake provide the conditions for calorie deficit which consequently results in losing weight.    While diet implies eating at regular intervals, fasting is the practice of not consuming food for a certain period or time intervals.                                                                              Various diets include or excluded particular food or propose eating in certain time intervals, but the most rigorous diet that is currently actual worldwide is intermittent fasting.

What is the difference between calorie restriction and fasting?

Calorie restriction considers a consistent reduction of daily calorie intake patterns. On the other hand, fasting focuses on eating frequency. Contrary to dieting, fasting doesn`t necessarily include calorie restriction during the non-fasting time. 


A fasting diet can have different varieties referring to the fasting time, and they are all commonly named “intermitted fasting”. The variations of intermitted fasting are:

  • Time-restricted feeding considers consuming meals usually every six or eight hours and restricts eating between these hours.
  • Alternate-day fasting means a person can eat unrestrictedly every other day, while no or minimum calories on the days of sating.
  • A 5:2 eating pattern implies five days of unrestricted eating followed by two days of the least possible calorie intake.
  • Periodic fasting refers to restricted eating for a few days (for example five days each month) while on other days there are no restrictions regarding the amount of calorie intake

What do studies say about fasting?

People who have voluntarily practiced extreme fasting for a couple of years have been noticed to have a lower risk of cardiovascular disease, heart disease, and diabetes. They also manifested effects on psychological aspects, reducing sexual interest, and the body’s ability to maintain body temperature in cold weather. Also, a slight reduction in bone density, periods of anemia, a decline in lean body mass, and aerobic capacity are some of the effects that fasting produced but this also applies to any weight loss, so it’s not considered as a consequence exclusively directed by fasting.

 However, more research and information are needed to determine the long-term effects of fasting, its risks, and its benefits.

Another occurrence that limits the distinguishing of the effects of fasting is the fact that most people who undergo fasting use different nutritional supplements and vitamins. This practice of taking supplements prevents identifying the real effect of calorie restriction versus other factors.

How does fasting work?

When the fasting body uses glucose and glycogen stored in the liver and muscles and energy stored in fat. This process releases energy in form of ketones, a chemical that helps cells to work at their very capacity. Ketones are particularly beneficial for brain cells and the theory links this chemical with preventing dementia and various disorders. Another theory about the advantages of fasting refers to the assumption that ketones are more efficient than glucose as the energy source. Additionally, some suggest that ketones can prevent the cancer cell from growing and expanding due to the cancer cells’ inability to efficiently attain energy from ketones. 

However, the presents of exaggerated ketones in the blood have a harmful effect on health.


Diet refers to moderate food intake, focusing on healthy eating at regular intervals, and doesn`t consider restricting food or water. There are numerous kinds of diets, but they are commonly grouped into four categories:

  • Low-fat diets
  • Low-carbohydrate diets
  • Low-calorie diets
  • Very-low calorie diet

Every diet considers producing a calorie deficit that will consequently result in weight loss. Different diets imply eating certain food and restriction others, some involve all food groups but focus on the number of calories you should intake on daily basis. Popular diets are the Mediterranean diet, Atkins diet, Keto diet, Flaxiterian, Vegan, Vegetarian, Paleo, Gluten-free diet, and many others.

What do the studies say about dieting?

Science suggests that having a healthy diet can only have a beneficial effect on health and the body. Having a balanced meal with low-fat food and sufficient necessary nutrients can help people lose weight, control diabetes, decrease blood sugar levels, reduce the risks of cardiovascular and heart diseases, and improve overall health. However, many diets that cut out certain food groups can cause a lack of nutrients and have negative effects such as anemia, fatigue, headache, nausea, and various other conditions. Although every diet will show positive results in terms of weight loss at least in the beginning due to metabolic changes in the body, a healthy diet considers the intake of enough calories and nutrients to obtain optimal functioning of an organism. 

How do diets work?

Every diet works by creating a calorie deficit. Calorie deficit affects the changes in metabolism. These changes usually refer to slowing the metabolism, which implies fewer calories are required daily. However, the efficiency of most diets lasts only until the metabolism gets used to the new eating manner and reestablishes its stability.

Strict dieting provokes the body to restrain fat and burn energy from muscles and lean tissue.

Diets with a certain food that suppress the secretion of hunger hormones show to be more successful in the long term. Still, diet is most often the insufficient way of losing weight without exercise that promotes calorie deficit while obtaining optimal metabolic rate.


As seen above, fasting and dieting both have their benefits on health if reasonably practiced. Even though both methods can result in weight loss, it’s important to consider your nutrient needs, age, body constitutions, and other individual characteristics before choosing any of these two options.

Even though both of these methods have a beneficial effect on weight loss and diabetes type 2, nowadays many overweight diabetics opt for ozempic weight loss as an efficient solution to their health condition and difficulties in losing weight.