Is Intermittent Fasting Easier Than Counting Calories?
A new study says the mental effort of dieting matters as much as the calories.
Key takeaway: Yes — a new 18-month University of Adelaide trial found intermittent fasting produced about the same weight loss as calorie counting, roughly seven kilograms over six months either way, but people on the fasting plan didn't report the constant mental effort of monitoring every bite. Researchers led by Professor Leonie…
By Dear Sarah · · Updated
Key takeaways
- A University of Adelaide trial of over 200 adults with obesity found intermittent fasting and calorie restriction produced similar weight loss, about seven kilograms over six months, compared to two kilograms with standard care.
- People following the fasting plan reported not needing to consciously monitor or restrict their eating, while the calorie-counting group described ongoing mental effort to limit intake.
- The fasting protocol tested was eating about 30 percent of daily calories between 8am and noon on three non-consecutive days a week, followed by a 20-hour fast, with normal eating on other days.
- The study was led by Professor Leonie Heilbronn and first author Xiao Tong Teong at the University of Adelaide and South Australian Health and Medical Research Institute, published in the journal Clinical Nutrition.
- Researchers say future work should focus on matching people who struggle with constant food monitoring to approaches that reduce that mental load, rather than assuming one diet fits everyone.
You know that particular kind of tired that has nothing to do with your body and everything to do with your brain? The one from a whole day of tallying, negotiating, second-guessing every bite before you've even taken it. New research says that mental tax might be the real reason so many diets fail, and it isn't about the food at all. A new 18-month clinical trial out of the University of Adelaide found that intermittent fasting produced almost the same weight loss as calorie counting, about seven kilograms either way over six months, but the people fasting didn't report white-knuckling their way there. They weren't tracking every gram or arguing with their own hunger all day. The relief, not the restriction, is what made the difference.
Is intermittent fasting easier than counting calories?
Based on this trial, yes, at least psychologically. More than 200 adults with obesity were randomized into three groups: intermittent fasting, continuous calorie restriction, or standard care. After six months, both the fasting group and the calorie-counting group lost around seven kilograms, compared to about two kilograms in standard care. The weight loss itself was a wash between the two approaches. What wasn't a wash was how it felt to get there. People on the fasting plan didn't describe needing to consciously monitor or restrict what they ate. People counting calories described the opposite: near-constant mental effort to keep themselves in check.
What the researchers actually found
The fasting protocol in the study wasn't extreme. Participants ate about 30% of their daily calories between 8am and noon on three non-consecutive days a week, then fasted for 20 hours, eating normally the rest of the week. Professor Leonie Heilbronn, who led the research at the University of Adelaide's School of Medicine and the South Australian Health and Medical Research Institute, put it plainly: "While many diets can result in weight loss, they may be difficult to stick to, and this makes keeping that weight off long-term more challenging." Her team, including first author Xiao Tong Teong, found that psychological and behavioral effects had a major influence on whether people could actually adhere to a diet over time, which is a very different question from whether a diet works in theory. The study, published in Clinical Nutrition, suggests future research should focus on matching people to the approach that reduces their mental load, rather than assuming one plan fits everyone.
Why this matters for you
A lot of us didn't grow up learning to trust our own hunger. We grew up learning to police it. Every "good" and "bad" food, every apology before eating dessert, every mental spreadsheet running in the background during a meal with friends, that's not discipline, that's a second job with no pay and no end date. This study is one of the first to put a number on what a lot of women already knew from experience: the diets that fail aren't necessarily the ones with the wrong macros, they're the ones that demand constant self-surveillance to work. If you've read the protein swap that's quietly changing how women eat, you already know that small structural shifts tend to outperform sheer willpower. The same logic shows up in new research on creatine and depression, where the food-mood connection kept surfacing specifically in the women studied. None of this is really about fasting as a rule to follow. It's about noticing where your food routine is asking you to fight yourself, and finding a way around that fight instead of trying to win it every single day. That's also the whole idea behind why healthy meals matter in the first place: consistency you don't have to force beats restriction you have to enforce.
One thing to try today
Skip the idea of starting a fasting plan tomorrow morning. Instead, pick one meal this week where you notice yourself relying on willpower instead of routine, maybe it's the 3pm snack decision, maybe it's dinner when you're exhausted, and build a boring, repeatable default for just that one meal. Same breakfast most days. A lunch you don't have to think about. One less decision your brain has to defend all day. If you have a history of disordered eating, skip fasting protocols entirely and talk to a professional you trust before changing how or when you eat; this isn't a rulebook, it's permission to stop treating your hunger like the enemy.
Quote to sit with
"I often wonder what my life would look like if I had learned that my body belongs to me, and me alone, first; that the way my body looks, and its purpose, is not to please others." — Florence Given
💌 Sarah
Frequently asked questions
Does intermittent fasting work better than counting calories for weight loss?
Not better exactly — in this trial, both groups lost about the same amount of weight, roughly seven kilograms over six months. The difference researchers found was psychological: people fasting didn't feel like they had to constantly police their eating, while calorie counters described ongoing mental effort to hold back.
What intermittent fasting schedule did the study use?
Participants ate about 30 percent of their daily calorie needs between 8am and noon on three non-consecutive days each week, then fasted for 20 hours. On the other four days, they ate their usual diet with no restrictions.
Is intermittent fasting safe for women?
The study population was adults with obesity, not a general population, so results don't automatically apply to everyone. If you're pregnant, breastfeeding, or have a history of disordered eating, fasting protocols aren't recommended without guidance from a doctor or dietitian you trust.
Why did fasting feel easier than calorie counting in the study?
Researchers found that the calorie-restriction group had to consciously monitor portions and resist overeating all day, which took ongoing mental effort. The fasting group didn't report needing to make those constant decisions, since their eating window did some of that work automatically.
Who led the intermittent fasting research?
Professor Leonie Heilbronn of the University of Adelaide's School of Medicine and the South Australian Health and Medical Research Institute led the study, with Xiao Tong Teong as first author. It was published in the journal Clinical Nutrition in 2026.
Sources
- Can't stick to a diet? Intermittent fasting may be easier than counting calories for weight loss — ScienceDaily
- Scientists Say Intermittent Fasting Could Make Weight Loss Easier — SciTechDaily
- Exploring the impact of intermittent fasting plus time-restricted eating versus calorie restriction on eating behavior, mood, sleep, quality of life in adults with obesity — Clinical Nutrition
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