Cheat day science: Does a cheat day help you lose weight?

Having a cheat day sounds counterintuitive to some, while perfectly fine to others. Let's look at cheat day science and try to answer the main question: does a cheat day help you lose weight? with the help of various studies and scientific experiments. 

Cheat day science Does a cheat day help you lose weight photo

1st study: Cheat day effect on self control, positive emotions and the desire to continue dieting

A study from 2015 split 36 participants into two groups that had to follow a 14-day long diet plan. One group was instructed to eat the same number of calories each day (1500), while the other group had a cheat day each week, which allowed them to eat 2700 calories. This group had to eat even less during the other 6 days of the week (1300 calories). Daily and weekly results and attitudes were monitored. Structure of the study:

  1. 36 participants that needed to lose weight were measured and selected to participate in the experiment and then split into two groups.
  2. General rules and guidelines about calorie consumption, water drinking needs, and other aspects were explained.
  3. During the dieting, participants had to answer relevant questions about self-regulation, their progress, and emotions on a daily basis while measuring their weight and BMI every week. 

The results of the study showed that:

  • The group without a cheat day rated their motivation to continue dieting, self-control, and positive emotions towards the diet more than 10 percent lower during the second week of the experiment.
  • The group with a cheat day had the opposite result. Their positive emotions increased 8 percent during the second week and the other two measures remained close to the first week's results.
  • Comparing those three measures between the two groups, the second week's results show about 15 percent more positive ratings in the group with a cheat day.
  • When asked about participants' desire to repeat the experiment, this desire was about 15 percent higher in the group that had a cheat day.
  • Both groups lost a similar amount of weight.

2nd study: How ego depletion affects weight loss

Ego depletion states that after resisting a temptation that requires willpower, you will have less willpower to resist the next temptation. A simple study had 39 participants watch sad videos and then participate in ice cream taste testing:

  1. Participants were split into two groups.
  2. One group had to watch sad videos while not showing emotions and keeping a straight face while the other had to watch the videos naturally.
  3. Then participants were led into an ice cream taste testing room to eat ice cream. 

The results of the study showed that the group that had to restrict their emotions while watching the sad videos, ate about 25 percent more ice cream compared to the group of people that watched the sad videos naturally. This shows how willpower is related to eating habits.

Dan Ariely (professor of psychology and behavioral economics at Duke University) states that restricting yourself to a strict diet that requires you to never indulge can make you more prominent to an ego depletion effect which can derail the diet. 


Having a cheat day can help people maintain the willpower which is required to succeed in the weight loss journey. More studies are needed to understand the higher-scale impact of the cheat day but the current studies suggest a positive impact that the cheat day brings.