- Counting calories is a proven method for weight loss, but many find it difficult.
- A new study suggests that intermittent fasting may be as effective as calorie-counting—and, for some, may require less mental effort.
- Dietitians say that while some may find intermittent fasting simpler to follow, it’s not for everyone.
Most people know that eating fewer calories than you burn—also known as practicing a calorie deficit—is a proven, effective weight-loss method. Unfortunately, it’s not always easy; counting calories can be a hassle.
The good news? New research suggests intermittent fasting may be as effective as calorie-counting for weight loss. Even better, it may require less mental effort.
For the study, published in Clinical Nutrition, scientists followed 209 adults with obesity with an average age of 58. For a period of six months, participants were randomly assigned to daily calorie restriction, general healthy eating habits, or intermittent fasting (in this case, participants were asked to eat 30% of their calories before noon, then fast for approximately 20 hours on three non-consecutive days per week). After the six-month intervention, the researchers continued tracking the participants’ weight, eating habits, mood, sleep, and quality of life for a year.
Meet the Experts: Lauri Wright, Ph.D., M.S., R.D.N., associate professor and director of the University of South Florida College of Public Health’s nutrition and dietetics program; Cay Schubert, L.C.S.W., social worker, psychotherapist, and owner at Fields That We Know; and Ilana Schachter, R.D.N., registered dietitian and nutritionist for Consumer Health Digest.
What did the study find?
Researchers found that participants assigned to intermittent fasting and daily calorie restriction both lost meaningful amounts of weight. They also experienced similar improvements in eating behaviors, mood, sleep, and quality of life.
Interestingly, those in the intermittent fasting group felt as though they expended less mental effort throughout their weight-loss journeys than those in the calorie-counting group. Conversely, the calorie counters felt that they became more focused on consciously limiting what they ate. “In other words, the two approaches may help people lose weight in different ways,” says Lauri Wright, Ph.D., M.S., R.D.N., associate professor and director of the University of South Florida College of Public Health’s nutrition and dietetics program.
One caveat: It’s important to note that participants didn’t have histories with disordered eating, and researchers didn’t collect any data about their bodies other than their weight. They did, however, measure participants’ disinhibition, “which, in layman’s terms, means binge eating or eating in a way that feels out of control, a common feature of eating disorders,” explains Cay Schubert, L.C.S.W., a social worker, psychotherapist, and owner at Fields That We Know. Intermittent fasting was found to increase disinhibition, which suggests that it would be an “extremely risky and probably psychologically harmful eating pattern for people who already have a history of binge eating or other disordered eating behaviors.”
How intermittent fasting works—and why it works better for some than others
Intermittent fasting doesn’t magically boost metabolism—rather, the study suggests it works mainly by helping people eat fewer calories. “Having set times for eating and fasting may make it easier to avoid constant snacking or mindless eating,” explains Wright. “Rather than thinking about calories all day, people simply follow a schedule, which some find easier to stick with.”
While intermittent fasting may feel simpler for some and can reduce decision fatigue, it’s not for everyone. “I consider a person’s medical history, relationship with food, lifestyle, medications, activity level, and hunger cues before recommending it,” says Ilana Schachter, R.D.N., a registered dietitian and nutritionist for Consumer Health Digest. “People with a history of eating disorders, individuals who are pregnant, some older adults at risk for inadequate protein intake or muscle loss, and certain people with diabetes requiring medication adjustments should approach fasting cautiously and discuss it with their healthcare provider.”
It’s also important to remember that intermittent fasting isn’t a panacea. “You can still overeat or choose mostly ultra-processed foods during your eating window, which can limit both weight loss and overall health benefits,” says Wright. “A balanced diet rich in fruits, vegetables, lean protein, whole grains, and healthy fats is still the foundation of good nutrition, whether you’re practicing intermittent fasting or not.”
The bottom line
“As a registered dietitian, I don’t think intermittent fasting is the ‘best’ diet. I think it’s one tool that works well for some people but not for everyone,” Wright says. “The best eating pattern is one that’s nutritious, fits your lifestyle, and is realistic to maintain long-term.”
Regardless of the approach, Schachter adds, a sustainable weight management plan should also prioritize strength training, fiber, sleep, stress management, and a positive relationship with food.
If you believe you are struggling with an eating disorder and need support, call the National Eating Disorders Association helpline at (800) 931-2237. You can text HOME to 741741 to message a trained crisis counselor from the Crisis Text Line for free.
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