// guides

Guides & how-tos

Plain-English answers to the questions the calculator raises — how to choose an activity level, when to recalculate, why progress stalls, and how the formulas actually work. Each guide links back to the tool it explains.

How to choose your activity level honestly

The activity multiplier is where most TDEE estimates go wrong. Here's how to pick honestly between sedentary, light, moderate, and active — with examples.

Why your TDEE feels too high

If your calculated TDEE looks higher than feels right, the activity multiplier is usually why. How to sanity-check and correct an inflated maintenance estimate.

When to recalculate your TDEE

Your TDEE isn't fixed — it falls as you lose weight. When to recalculate: weight-change thresholds, plateaus, and activity changes, explained simply.

Why weight loss stalls even when you're in a deficit

Stalled despite eating in a deficit? The most common causes in order of likelihood — intake drift, water retention, and real metabolic adaptation — and how to fix each.

Why you should never eat below your BMR

Eating below your BMR isn't a faster route to fat loss — it's a fragile one. What BMR represents, why it's the floor, and how to set a deficit from TDEE instead.

How fast can you safely lose weight?

The safe, sustainable rate of weight loss explained: why 0.5–1% of body weight per week is the sweet spot, and what faster loss actually costs you.

Reverse dieting: how to come off a cut without rebound

Finished a diet and afraid of regaining? Reverse dieting means raising calories gradually back to maintenance. How it works, how fast to add calories, and why.

BMR vs RMR — are they the same?

BMR and RMR are often used interchangeably, but they're measured differently and RMR runs slightly higher. What each means and which one calculators actually give you.

Which BMR formula is most accurate, and why it depends

Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle? Which BMR equation is most accurate, when each wins, and why the right answer depends on what you can measure.

Should you eat back exercise calories?

Apps add calories back when you exercise — should you eat them? Why exercise burns are overestimated, and how your activity multiplier already accounts for training.

Is my metabolism damaged?

Worried about a 'damaged' or 'starvation mode' metabolism after dieting? What the science actually shows about metabolic adaptation — real but small — and how to recover.

Does BMR change with age, and how much?

Your BMR does fall with age — but more slowly than most think, and recent research reshaped the picture. What drives the change and how much it really matters.

Why two people of the same weight have different BMRs

Same height and weight, different calorie needs? Body composition, sex, age, and genetics all shift BMR — which is why a formula is a starting estimate, not a verdict.

BMI limitations for athletes and older adults

BMI misclassifies muscular athletes as overweight and can miss risk in older adults. Where BMI breaks down, who it fails, and what to use alongside it.

What's a healthy body-fat percentage by age and sex?

Healthy body-fat percentage ranges differ by sex and rise gently with age. The general reference bands, why women's are higher, and how it complements BMI.

How to set a calorie deficit without crashing

A sustainable calorie deficit comes from TDEE, stays above BMR, and is sized to lose 0.5–1% of body weight a week. How to set one that lasts — not one you abandon.

Maintenance calories: how to find and hold yours

Maintenance calories are where weight holds steady — your TDEE. How to estimate it, confirm it from your weight trend, and hold a stable weight once you find it.

How to split macros once you know your calories

Got your calorie target? Here's how to turn it into protein, carbs, and fat — set protein and fat by body weight first, then fill the rest with carbs.

How much protein per kg, actually?

Protein advice ranges from 0.8 to over 2 g/kg. What each figure is for — minimums vs. muscle-retention vs. dieting — and the practical target for most people.

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