Science and Tech


Which works better: Intermittent fasting or calorie counting?

Researchers at the University of Chicago studied whether intermittent fasting worked any better than calorie counting for weight loss.
Diet plan paper with pencil.
Posted at 10:58 AM, Jun 27, 2023

Many dieters have praised intermittent fasting as a way to lose weight, but is it any better than just simply watching what you eat?

According to a new analysis from researchers at the University of Chicago, the answer is no. 

The research included 90 adults with obesity whose eating behavior was monitored for a year. The participants were placed into three groups:

- Intermittent fasting group with no calorie restriction, but only ate between noon and 8 p.m.

- A group that counted calories

- Control group that ate over a period of 10 or more hours per day

Seventy-seven participants finished the study. It found that those who practiced intermittent fasting lost an average of 4.61 kilograms (10.61 pounds). Those who used a calorie-restricted diet had lost 5.42 kilograms (11.95 pounds). The researchers said the differences between the two groups were not statistically significant. 

"Time-restricted eating is more effective in producing weight loss when compared with control but not more effective than CR in a racially diverse population," the study concluded. 

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The University of Chicago has conducted multiple studies on the benefits of intermittent fasting. In 2021, it conducted research that found that various forms of intermittent fasting led to mild to moderate weight loss. 

“You’re fooling your body into eating a little bit less and that’s why people are losing weight,” said researcher Krista Varady.

Varady previously said that intermittent fasting does not negatively affect someone's metabolism. 

"Fasting people are worried about feeling lethargic and not being able to concentrate. Even though you are not eating, it won’t affect your energy," Varady said. "A lot of people experience a boost of energy on fasting days. Don’t worry, you won’t feel crappy. You may even feel better."

The University of Chicago says the following groups should not consider intermittent fasting: 

- Those who are pregnant or lactating. 

- Children under 12. 

- Those with a history of disordered eating. 

- Those with a body mass index, or BMI, less than 18.5.

- Shift workers. Studies have shown they may struggle with fasting regimens because of shifting work schedules. 

- Those who need to take medication with food at regimented times. 

A Chinese study released last year also indicated little difference between intermittent fasting and calorie counting.

"These results indicate that caloric intake restriction explained most of the beneficial effects seen with the time-restricted-eating regimen. Even so, our findings suggest that the time-restricted–eating regimen worked as an alternative option for weight management. We speculate that these data support the importance of caloric intake restriction when adhering to a regimen of time-restricted eating," the study read.