Keto, IF or counting calories — which suits whom?
All three work the same way: they make you eat less than you use. They differ only in which variable they restrict — keto restricts what you eat, IF restricts when, counting restricts how much. Long-term comparisons find similar results, so the deciding factor is which one you will still be doing in month six.
"Which is best" cannot be answered the way people want it answered. "Which suits whom" can.
What actually differs between them?
All three do the same thing — put energy in below energy out. They differ in which variable they pick up.
- Keto restricts what you eat — carbohydrate goes, the rest is eaten to fullness.
- IF restricts when you eat — nothing is forbidden inside the window.
- Counting restricts how much — nothing is forbidden and no hour is either.
None of them burns fat on its own. Each is a rule designed to let someone comply without deciding afresh at every meal.
What do the trials say about which works better?
Followed for a year, the differences are small. DIETFITS (Gardner 2018) compared low-carbohydrate with low-fat in 609 people over 12 months: 6.0 kg against 5.3 kg, not a significant difference. Liu and colleagues (2022) in the New England Journal of Medicine compared time-restricted eating plus calorie restriction against calorie restriction alone in 139 people over 12 months, and found no difference.
What both studies found, and what matters more than the averages, is that the variation between individuals within a group was far larger than the variation between groups.
So how should you choose?
From the life you actually have, not from the mechanism. A few questions settle it.
- Do clear rules help you, or chafe? If a bright line between allowed and not-allowed makes things easier, keto suits. If prohibitions make you rebel, counting suits better.
- Are you hungry in the morning? Someone who never is can do IF with almost no adjustment. Someone who wakes up ravenous will be fighting it daily.
- How often do you eat out? Keto is hardest in that situation; IF is easiest.
- Can you tolerate logging? Counting is the most accurate and demands the most consistency.
Can you combine two of them?
Yes, and many people already do without meaning to. But every rule you stack adds a place to fail, and the day one rule breaks tends to take the rest with it.
The safer advice is to start with one, live with it for four to six weeks, and only then ask whether another layer is genuinely needed.
What none of the three takes care of
None of them says anything about protein or resistance training, which are the two things that decide whether the weight you lose is fat or muscle. Whichever you choose, you have to add those yourself.
And none of them mentions sleep, which is the variable you can fix without changing a single thing about the food.
Reading something you can act on beats reading something you cannot.