Topic

Adaptive calorie targets

Your calorie target is a guess, and it was only ever a guess about an average person. Bodies do not stay still, so a number that fitted you in January can quietly stop fitting by March. These guides explain what makes a target drift and what a target that updates itself is watching.

Most apps hand you a number on day one and leave it there. That number came out of an equation using your height, weight, age and sex, and it never saw you move around, sleep badly, or have a stressful fortnight.

We care about this because it changes how a stall feels. If you believe the target is correct, a flat week on the scale looks like your failure. If you know the target is an estimate with a shelf life, the same week reads as a signal to adjust, which is a far more useful thing to be told.

The guides here cover the moving parts: the everyday movement that changes without you noticing, what happens to energy use during a long deficit, why two people on identical plans end up somewhere different, and why the number is worth revisiting. All of it applies just as much if you are trying to gain weight.

20 guides

Guides in this topic

5 min read

How Many Calories Do I Burn a Day?

The NHS says women use about 2,000 calories daily and men about 2,500. Tables by age, weight and activity, what you burn doing nothing, and how to find yours.

6 min read

What Is a Calorie Deficit? A Simple Guide

A calorie deficit means using more calories than you eat and drink, so your body uses its fat stores. How it works, how big it should be, and how to tell.

6 min read

How Many Calories Should I Eat to Lose Weight?

The NHS suggests eating about 600 calories a day less than now. Targets by weight for women and men, how fast you'll lose, and what to do if you stall.

5 min read

How Many Calories Should a Man Eat a Day?

The NHS says an average man needs about 2,500 calories a day. Tables by age, activity and weight, how much to eat to lose weight, and how to find your number.

5 min read

How Much Weight Can You Lose in a Month?

It depends on how much you have to lose and how big your cut is. A steady pace is 2 to 4 kg (5 to 9 lb) a month. Why month one shows more, and a stone a month.

5 min read

How Many Calories Should a Woman Eat a Day?

The NHS says an average woman needs about 2,000 calories a day. Tables by age, activity and weight, how much to eat to lose weight, and how to find your number.

5 min read

How Many Calories Are in a Pound of Fat?

About 3,500 calories (7,700 per kg). Where the 1958 rule comes from, how many calories it takes to lose a pound, and why it overestimates weight loss.

6 min read

Reverse Dieting: What It Is and Does It Work?

Reverse dieting means adding calories back slowly after a diet. What it involves, what a 2025 trial found, and how to come off a diet without regaining.

5 min read

Not Gaining Weight in a Calorie Surplus?

Eating more but the scale won't move? 5 common reasons you're not gaining weight in a calorie surplus, how long to wait, and how much more to eat.

5 min read

Why Am I Tired and Weak in a Calorie Deficit?

Tired or weak in a calorie deficit? Usually the gap is too big, sleep is short or training outpaces food. How to tell which, simple fixes, and when to see a GP.

5 min read

Is 1,200 Calories Enough, or Too Little?

Is 1,200 calories enough? Not for most men. For most women it's a bigger cut than the NHS suggests, and UK guidance calls it a low-calorie diet.

7 min read

Does a Calorie Deficit Make You Lose Muscle?

How much muscle you lose in a calorie deficit depends on how lean you are and how fast you lose weight. Strength work, protein and a slower pace help.

6 min read

Is It Normal to Be Hungry in a Calorie Deficit?

Yes, some hunger is normal in a calorie deficit. Constantly hungry? The gap may be too big, or meals low in protein or bulk. How to tell and feel fuller.

6 min read

How to Find Your Maintenance Calories

How to find your maintenance calories: the formula calculators use, why it can be off, and how a few weeks of logging gets a number that fits you.

5 min read

Weight Loss Plateau: Why Has It Stopped?

A weight loss plateau usually means water is hiding fat loss, you're eating a bit more without noticing, or your target is out of date. What to do.

4 min read

How Long for a Calorie Deficit to Show Results?

Usually 2 to 4 weeks on the scale. Why week one can drop fast or barely move, and how to read the scale while you wait.

10 min read

Diet Breaks: Do They Work for Weight Loss?

Four randomised trials tested planned breaks from a calorie deficit. None showed faster fat loss in lean dieters, and the evidence they feel easier is mixed.

4 min read

Why Do People Lose Weight at Different Rates?

In a 609-person trial, results on the same diets ranged from a 30 kg loss to a 10 kg gain. Why your rate differs, and why it's rarely about willpower.

4 min read

What Is NEAT? The Calories You Burn Unnoticed

NEAT calories are what you burn through everyday movement, not exercise. They can shift by hundreds a day without you noticing, in either direction.

6 min read

Why Your Calorie Target Shouldn't Stay the Same for Months

Your calorie target should be adjusted often and not fixed for months, no matter if you're trying to lose weight or gain it.

Other topics

More from Ori Blogs