📊 Nutrition Science
How Many Calories in a Stone?
One stone of body fat stores approximately 49,000 calories. Here is the full maths, what it means for your weight loss plan, and the nuances nobody explains.
Medical disclaimer: This is general information, not medical advice. Speak to your GP before starting a weight-loss programme, especially if you have a health condition, take medication, are pregnant, or have a history of disordered eating.
The Short Answer
One stone (14 lb) of body fat = approximately 49,000 calories.
The calculation: 14 pounds × 3,500 kcal per pound = 49,000 kcal. To lose a stone, you need a total energy deficit of about 49,000 calories through eating less, moving more, or (ideally) both.
But the 3,500 kcal rule is a simplification. This article covers the full picture. For practical plans, see how to lose a stone.
Where Does 3,500 kcal/lb Come From?
The figure originates from researcher Max Wishnofsky's 1958 calculation. Pure fat contains about 9 kcal per gram. One pound (454g) of pure fat would be ~4,086 kcal. But body fat tissue is not pure fat; it contains water, protein, and cellular structures. Adjusting for this gives approximately 3,500 kcal per pound of adipose tissue.
Modern research shows the real number varies:
| Tissue Type | Calories per Pound | Notes |
|---|---|---|
| Body fat (adipose) | ~3,500 kcal | Standard figure; varies 3,000-3,700 |
| Muscle tissue | ~600 kcal | Mostly water and protein |
| Pure dietary fat | ~4,086 kcal | 9 kcal/g × 454g |
Why this matters: if you lose muscle instead of fat (common in crash diets without strength training), each pound lost represents far fewer calories. Preserve muscle with protein and resistance training.
What 49,000 kcal Looks Like in Practice
| To Burn 49,000 kcal… | Equivalent |
|---|---|
| Running (100 kcal/mile) | 490 miles |
| Walking (80 kcal/mile) | 612 miles |
| Big Macs (563 kcal each) | 87 Big Macs |
| Pints of lager (180 kcal each) | 272 pints |
| Days at 500 kcal deficit | 98 days (~14 weeks) |
The exercise-only route shows why diet matters more than exercise for weight loss. You cannot outrun 49,000 calories, but you can eat 500 fewer per day for 14 weeks.
Timeline: How Long to Create a 49,000 kcal Deficit
| Daily Deficit | Days to 49,000 kcal | Weekly Fat Loss |
|---|---|---|
| 250 kcal | 196 days (28 weeks) | ~0.5 lb |
| 500 kcal | 98 days (14 weeks) | ~1 lb |
| 750 kcal | 65 days (9 weeks) | ~1.5 lb |
| 1,000 kcal | 49 days (7 weeks) | ~2 lb |
The NHS recommends 1 to 2 lb per week, putting a stone at 7 to 14 weeks. See how long to lose a stone for the detailed timeline.
Why Your Actual Number Varies
- • Body composition: leaner people lose more muscle per pound, lowering the calorie value
- • Metabolic adaptation: metabolism slows as you lose weight
- • Protein intake: high protein (1.6-2.2g/kg) preserves muscle
- • Strength training: signals your body to retain muscle
- • Starting weight: heavier people initially lose faster
This is why weight fluctuates daily and why plateaus happen.
Frequently Asked Questions
How many calories are in a stone?
One stone (14 lb) of body fat contains approximately 49,000 calories, based on the widely used figure of 3,500 kcal per pound of body fat. To lose a stone, you need a total calorie deficit of about 49,000 kcal.
How many calories do I need to burn to lose a stone?
You need a total deficit of approximately 49,000 kcal. At a daily deficit of 500 kcal, this takes about 14 weeks. At 1,000 kcal daily deficit, about 7 weeks. The NHS recommends 1 to 2 lb per week, meaning 7 to 14 weeks for a stone.
How many calories in a stone of fat vs muscle?
A pound of body fat stores about 3,500 kcal, while a pound of muscle stores only about 600 kcal. This is why preserving muscle during weight loss matters: losing muscle instead of fat means losing less stored energy per pound.
Is the 3,500 calorie rule accurate?
The 3,500 kcal per pound rule is a useful approximation but simplifies reality. Research suggests the real figure ranges from 3,000 to 3,700 kcal per pound depending on body composition, metabolic adaptation, and the proportion of fat vs lean tissue lost.
How many calories should I eat per day to lose a stone?
The NHS suggests around 1,400 kcal per day for most women and 1,900 kcal for most men when losing weight. This typically creates a 500 to 750 kcal daily deficit, targeting 1 to 1.5 lb of fat loss per week.
How long does it take to burn 49,000 calories?
Through exercise alone, a very long time. Running burns roughly 100 kcal per mile, so 49,000 kcal equals about 490 miles of running. Combined diet and exercise is far more effective: a 750 kcal daily deficit reaches 49,000 kcal in about 9 weeks.
Related Guides
How to Lose a Stone
Complete weight loss guide
How Long to Lose a Stone?
Realistic timelines
Can You Lose a Stone in a Month?
Feasibility and maths
What Is a Stone?
The unit explained
Water Weight vs Fat
What the scale really shows
Weight Loss Tracker
Track your stone progress
Reviewed by the StoneToKg editorial team. Last updated October 2026. Calorie figures based on Wishnofsky (1958) and Hall et al. metabolic research.