Which is better for weight loss: Intermittent Fasting or Caloric Restriction?

In a recent post I introduced the concept of intermittent fasting and keto diet. I also talked about how they can be effectively used to lose weight. In a response to this post, one of our readers commented ,”Intermittent fasting may be too hard for beginners to follow. A better approach would be caloric restriction.” So in this post we will compare which dietary practice is better for weight loss : intermittent fasting or caloric restriction.

What is caloric restriction ?

Caloric restriction is a dietary practice in which an individual reduces his average daily calorie intake below what is typical or usual, without reaching a state of malnutrition or depriving himself of the essential nutrients that the body needs. So let’s say earlier he used to consume 2500 calories per day, eating in a caloric restricted way would mean that now he would consume around 1750-2000 calories per day.

 

Why restricting your calories results in weight loss ?

The idea why caloric restriction results in weight loss is that, suppose presently your body needs 2500 calories per day to maintain it’s current body weight. If you have lesser than 2500 calories per day, then your body will burn the fat that is stored inside your body, to make up for the caloric deficit, so that you can carry out your regular day to day activities.

 

Talking about Intermittent Fasting 

While many dietary concepts may come and go, the concept of intermittent fasting has been around for centuries. Intermittent fasting involves alternating between periods of fasting, ranging from a few hours to more than a day, with periods of unrestricted eating. The cycle of fasting and eating can either repeat daily, or alternate between day(s) of complete fasting followed by day(s) of unrestricted eating.

Let’s now discuss different types of intermittent fasting :

1. Time-restricted eating

In this type of intermittent fasting, the individual chooses a limited number of hours during which he can eat. The fasting period lasts between 14-18 hours. During the fasting period, you can’t consume any calories. One can only eat during the remaining hours of the day.

2. Alternate day fasting :

As opposed to time restricted eating, alternate day fasting means that each phase of the eating-fasting cycle lasts for one or more days, rather than hours. This type of fasting dictates that a person should alternate between day(s) of no or minimal food and day(s) of unrestricted eating.

 

How Intermittent fasting fares against caloric restriction

To compare the effects of caloric restriction versus intermittent fasting, let’s now turn our attention to a study carried out by scientists in UK. In order to investigate the effects of caloric restriction versus intermittent fasting the researchers in UK carried out a study. For the study they recruited a group of 36 healthy adults for the study. The scientists divided the population into 3 groups. The participants in the first group practiced caloric restriction during the study, consuming 25% lesser calories each day. The second group practiced alternate day fasting, alternating between a day of eating in caloric surplus(150 % calories) and a day of fasting. Such that there average caloric deficit was same as the first group. The third group was a control group and so had the same amount of calories as their maintenance calories .

The participants underwent various lab tests after the 3 week intervention. The tests revealed that those in the calorie restricted  group lost an average of 1.91 kilograms (kg) at the end of the study period. Meanwhile, those fasting were on an overall caloric deficit and lost an average of 1.60 kg.

The slightly greater loss in weight for those on a calorie restricted diet, as compared to those who practiced intermittent fasting(alternate day fasting), can be attributed to the fact that fasting resulted in lower energy levels. Therefore those who fasted indulged in lesser physical activities and hence burnt lesser number of calories compared to participants of the first group. Thus going by this study, it’s safe to say that, as long as there’s the same overall caloric deficit, both caloric restriction and intermittent fasting have almost the same effect on weight loss. However, things in real life aren’t so black and white.

 

Ermmm… but there’s a catch !

 

In the long term if we want to be fit and healthy, we need to make good eating habits part of our daily life. There will be days when you will have to go out to parties and eat in social groups. Unless you have a computer that’s ingrained in your brain, its not practically possible during such times, to count the calories before putting the food on your plate.

Whereas, if you practice intermittent fasting, especially time restricted eating, and restrict yourself to only eat during a specific number of hours each day, then you can eat out without inhibitions as long as you avoid less caloric dense foods(e.g:  junk food) and focus more on healthy foods. This is because there is only so much a person can eat in a restricted time frame.  Also since healthy foods  are generally less calorie dense and make you feel fuller for a longer amount of time, they will help you feel fuller without burdening you with excess calories.

Therefore when it comes to weight loss, the practice of caloric restriction produces the same results as time restricted fasting. However due to the long term infeasibility of the approach of keeping a daily count of one’s calories, it’s better to practice time restricted eating.

Thanks for reading ! 🙂

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