- Both intermittent fasting and calorie counting are popular ways to lose weight.
- Some prefer intermittent fasting to calorie counting since it is simpler to follow.
- However, it has been unclear whether both are equally effective long term.
- A new study found that both led to about the same amount of weight loss over the course of a year.
- Experts say the choice between the two may come down to individual preferences and needs.
When it comes to weight loss, there are several methods available. However, two that remain popular are traditional calorie counting and intermittent fasting.
Calorie counting can involve quite a bit of label reading and record keeping, which many find burdensome to maintain.
On the other hand, many like the simplicity of intermittent fasting (IF), which is more focused on the when of eating rather than the what.
Some popular variations of intermittent fasting include alternate-day fasting, in which people alternate fasting days with days of normal eating; 5-2 fasting, in which people eat normally for five days and then abstain from eating for the other two; and daily time-restricted eating, in which people eat during a set feeding window while fasting for the remaining of the 24-hour period.
However, one thing that remains unsure is whether intermittent fasting has the same effectiveness as calorie restriction for long-term weight loss.
The good news for dieters, though, is that it does appear that both eating plans can lead to an approximately equal amount of weight loss.
And, given this fact, it may be more up to personal preferences which plan is best for any given individual.
Dr. Krista Varady, Professor of Nutrition at the University of Illinois Chicago, who authored the study published in Annals of Internal Medicine, said, “Time-restricted eating, without calorie counting, has become a popular weight loss strategy because it is simple to do.”
However, she noted that it’s uncertain whether this approach really helps with weight loss beyond the short term.
Additionally, it’s not known whether it’s more effective than traditional diets that count and restrict calories.
“Our study is first to compare time-restricted eating (without calorie counting) to traditional dieting (calorie counting) for weight loss over 12 months in people with obesity,” she observed.
Her team’s study included 90 racially diverse adults with obesity from the greater Chicago area. Of these, 77 finished the entire study.
Each person was given a random assignment to one of three groups: 8-hour time-restricted eating (eating between 12:00 p.m. to 8:00 p.m. daily without calorie counting), calorie restriction (calories slashed by 25%); or no changes in eating pattern. Additionally, those in the time-restricted eating group were allowed to drink no-calorie liquids outside their feeding window.
The time-restricted eating and calorie-restriction groups both had biweekly sessions with a dietician for 6 months while they were losing weight. They then met monthly with a dietician for the next 6 months during a weight maintenance phase.
All groups received measurements at the onset of the study, at the 6-month point, and at 12 months.
The participants were requested to not change their activity level or add exercise to their routine.
Varady said that her team found that people who practiced time-restricted eating ate 425 fewer calories daily than those who were not following any sort of eating plan (the control group).
Additionally, they lost about 10 more pounds during the year of the study.
On the other hand, those who restricted their caloric intake ate about 405 fewer calories per day.
They lost around 12 more pounds in one year than the control group.
Varady noted that both groups showed high adherence to their eating plans.
“We also found that participants who engaged in 8-hour time-restricted eating had improved insulin sensitivity compared to those in the control group who ate their calories any time over 10 or more hours a day,” she added.
The net result when it comes to weight loss? Both groups had about the same degree of calorie restriction (400 calories per day) and weight loss (5%) over the course of the study.
“Time-restricted eating may be an attractive alternative to traditional dieting, since it is easy to follow, free, and very accessible,” said Varady. “Anyone who has access to the time can do this diet.”
Megan Hilbert, a Registered Dietitian with Top Nutrition Coaching who was not a part of the study, said that, based on the findings of this study and others, she would not necessarily recommend one style of eating over the other.
Instead, she would find what feels more doable for her clients over the long term.
“The most important factor in choosing a style of eating to help with weight loss is to look at longevity,” she said. “[W]ill you be able to stick to these habits for years?”
For most people, calorie counting feels restrictive and can be hard to maintain for long periods of time, Hilbert explained.
In the long term, calorie counting leads to a reduction in the basal metabolic rate (BMR), which is the number of calories your body needs to carry out its basic functions. It also promotes an increase in hormones that make you feel hungrier. Both of these changes can result in weight gain.
On the other hand, the effects of intermittent fasting on these hunger hormones are not as well understood, according to Hilbert.
“For some individuals eating at regular intervals helps with concentration, mood, energy, and fullness so IF may not be the best fit for them,” she said.
In conclusion, Hilbert noted that, while these findings are promising, more robust research is needed to confirm them.
However, in the meantime, it appears that an individual’s personal preferences and needs may be the deciding factor in which weight loss method they should choose.