You've been eating the same amount and exercising consistently for months. The scale moved well at first, then slowed, and now it's completely stuck. Nothing has changed. You're doing everything right. And yet the results have stopped. This experience is so common it has its own name: the weight loss plateau. And while it can feel like your body is conspiring against you, the explanation is physiological, predictable, and — once you understand it — actually manageable.
BMR and TDEE: The Two Numbers That Drive Everything
Your Basal Metabolic Rate (BMR) is the calories your body burns at complete rest just to maintain basic functions — breathing, circulation, organ function, temperature regulation. It's a function of your body weight, height, age, and sex. A heavier body has a higher BMR than a lighter body, because there's more tissue to maintain.
Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor to account for movement throughout the day. A sedentary person's TDEE might be 1.2 times their BMR; a very active person's might be 1.7 times their BMR.
Both numbers fall as you lose weight. This is the central mechanism behind the plateau.
Why the Calorie Deficit Shrinks Automatically
Say you started at 90kg with a TDEE of 2,400 calories. You set a daily intake of 1,900 calories — a 500-calorie deficit targeting 0.5kg per week. Over six months of consistent eating and exercise, you lose 12kg and now weigh 78kg. Your TDEE at 78kg might be 2,200 calories. Your still-eating-1,900-calories deficit is now only 300 calories per day — producing weight loss of roughly 0.3kg per week instead of 0.5kg.
Carry on, and by the time you're at 72kg with a TDEE of 2,100 calories, that same 1,900-calorie intake is only 200 calories below maintenance. Weight loss has nearly stalled — not because anything went wrong, but because the maths changed while the calorie intake stayed fixed.
Use our calorie calculator to recalculate your TDEE at your current weight every 4-6 weeks and adjust your calorie target accordingly. Treating TDEE as a fixed number throughout a weight loss journey is one of the most common reasons for unexpected plateaus.
Metabolic Adaptation: The Additional Layer
Beyond the straightforward reduction in TDEE from being lighter, there's an additional phenomenon: adaptive thermogenesis, often called "metabolic adaptation." The body responds to sustained calorie restriction by becoming more efficient — reducing NEAT (non-exercise activity thermogenesis, essentially unconscious fidgeting and low-level movement), decreasing the thermic effect of food, and lowering the metabolic rate slightly beyond what the weight reduction alone would explain.
Research suggests this adaptation can reduce calorie burn by an additional 100-200 calories per day beyond the weight-related TDEE reduction. This is the body's evolutionary response to what it perceives as famine — it's trying to help you survive by using fuel more efficiently. It's not helpful when you're trying to lose fat in 2026, but it made excellent sense for our ancestors facing genuine food scarcity.
Our TDEE calculator provides a starting point for recalibration, but adaptive thermogenesis means the actual number may be modestly lower than the formula suggests during prolonged restriction. Tracking food accurately and observing actual weight trends over 3-4 weeks is the most reliable way to find your true maintenance calories at any given point.
What to Do When Progress Stalls
First: recalculate your TDEE at your current weight and adjust calories downward if needed. A modest reduction of 100-200 calories can restore meaningful progress without dramatically increasing hunger or energy depletion.
Second: audit tracking accuracy. As a diet progresses, logging often becomes less precise — smaller portions aren't weighed, condiments go untracked, occasional extra snacks aren't recorded. Spending one week logging with rigorous accuracy frequently reveals that intake crept up while the attention was elsewhere.
Third: consider a structured diet break. Two to four weeks eating at maintenance calories — genuinely at maintenance, not slightly above — can partially reverse metabolic adaptation, restore training performance, and improve psychological sustainability before resuming the deficit. Research supports diet breaks as a tool for improving long-term fat loss outcomes compared to continuous restriction.
Training and Metabolism
Resistance training helps preserve metabolic rate during a cut by maintaining muscle mass. Muscle tissue is metabolically expensive — it raises BMR — and losing muscle during a deficit accelerates the TDEE reduction. Prioritising resistance training and adequate protein intake is not just about aesthetics; it's about maintaining the metabolic engine that makes fat loss sustainable.
The NHS evidence review on obesity treatment approaches discusses metabolic factors in weight management and is worth reviewing for anyone experiencing persistent difficulty with weight loss despite consistent effort.
The Mental Side
Plateaus are demoralising. They feel unfair, especially when genuine effort has been sustained. Understanding the physiological explanation — your TDEE changed while your intake didn't — converts the plateau from evidence of failure to a simple calibration problem. Adjust the numbers. Resume progress. You didn't do anything wrong.