Why Do Some People Lose Weight Faster Than Others?
Why Do Some People Lose Weight Faster Than Others?
You start trying to lose weight at the same time as somebody else.
You are eating differently, moving more and trying to make sensible choices.
A few weeks later, they seem to have lost considerably more weight than you.
It can be frustrating, but it is also completely normal.
People do not lose weight at exactly the same speed.
Your starting weight, body composition, genetics, age, hormones, activity levels, appetite, sleep, medical conditions and even some medicines can all influence how quickly your weight changes.
So if somebody else appears to be losing weight faster than you, it does not necessarily mean they are doing something better.
Here are some of the main reasons weight loss can look very different from one person to another.
1. Your Starting Weight Makes a Difference
Someone who starts at a higher body weight may lose more kilograms or pounds than someone who starts lighter, even if both are losing a similar percentage of their starting weight.
For example:
- Someone weighing 120 kg who loses 5% of their body weight has lost 6 kg
- Someone weighing 80 kg who loses 5% has lost 4 kg
The first person has lost more on the scales, but proportionally their results are identical.
This is one reason comparing weight loss purely in pounds or kilograms can be misleading.
Looking at your percentage of weight lost can sometimes give a better picture of your own progress.
2. Some People Naturally Burn More Energy
Your body uses energy constantly, even when you are doing nothing.
Energy is needed for things such as:
- Breathing
- Circulation
- Maintaining body temperature
- Brain function
- Digestion
- Movement
The amount of energy your body uses varies between individuals.
Body size and muscle mass can both influence this.
Someone with a larger body or more lean muscle will generally require more energy than a smaller person, so two people eating exactly the same number of calories may not experience identical results.
This is why there is no single calorie intake that produces the same rate of weight loss for everyone.
3. Genetics Can Play a Part
Genetics can influence how easily somebody gains weight and how their body responds to changes in food intake and activity.
The NHS includes genetics among the factors that can make maintaining a healthy weight more difficult for some people.
Genes can influence characteristics such as:
- Appetite
- Hunger
- Body fat distribution
- Energy expenditure
- Food preferences
- How readily the body stores excess energy
This does not mean your genes determine your weight completely.
It simply means some people may have to work against different biological pressures than others.
4. Men and Women May Lose Weight Differently
Body composition differs considerably between individuals and often between men and women.
Men tend, on average, to carry more lean muscle mass, while women naturally require a higher proportion of body fat.
Because muscle uses energy, differences in body composition can affect overall energy expenditure.
Hormonal changes can also influence weight and fat distribution.
The NHS specifically recognises menopause and perimenopause as factors that can make maintaining a healthy weight more difficult.
So comparing your progress with your partner, friend or colleague may not be particularly useful, even if you are following similar routines.
5. Age Can Affect Weight Loss
Weight management can change as we get older.
People may become less active, lose some muscle mass and experience hormonal changes as they age.
The NHS notes that being over 55 can be one of several factors associated with finding it harder to maintain a healthy weight.
That does not mean weight loss becomes impossible.
It simply means the approach that worked easily at 25 may not produce exactly the same results at 45 or 60.
6. Your Daily Activity May Be Very Different
Two people can both say they "exercise three times a week" while having completely different overall activity levels.
One person may:
- Walk to work
- Spend all day on their feet
- Take the stairs
- Walk the dog
- Do household jobs
- Exercise several times each week
Another may exercise for an hour but spend most of the remaining day sitting.
All of that movement contributes to energy expenditure.
This is why daily activity outside formal exercise can matter too.
NICE recommends increasing physical activity as part of weight management, while recognising that physical activity provides important health benefits even when it does not produce weight loss by itself.
7. People Often Eat Different Amounts Without Realising It
Two meals that look almost identical can contain very different numbers of calories.
Small differences can add up through:
- Portion sizes
- Cooking oils
- Sauces
- Dressings
- Snacks
- Alcohol
- Sugary drinks
- Coffees
- Weekend meals
- Tasting food while cooking
This does not mean you need to obsessively count every calorie.
But it explains why two people who believe they are following the "same diet" may actually be consuming different amounts of energy.
For weight loss to occur, energy intake generally needs to be lower than energy expenditure over time. NICE describes this as an energy or calorie deficit.
8. The First Few Weeks Can Be Misleading
Some people experience a large drop on the scales when they first change their diet.
Others see much slower movement.
Early changes on the scales are not necessarily all body fat.
Your weight can fluctuate because of:
- Water
- Food and drink in your digestive system
- Salt intake
- Carbohydrate intake
- Hormonal changes
- Bowel movements
That means somebody losing several pounds in their first week has not necessarily lost that amount of body fat.
Similarly, a week where the scales barely move does not automatically mean nothing is happening.
It is usually more useful to look at the trend over several weeks than one individual weigh-in.
9. Sleep Can Affect Weight Management
Sleep is often overlooked.
How much sleep you get is one of the factors that can influence weight, alongside diet, activity, health conditions, medicines and genetics.
Poor sleep can also make sticking to healthy routines harder.
If you are exhausted, you may be:
- Less active
- More likely to reach for convenient food
- Less motivated to exercise
- More likely to snack
Weight management is rarely just about what happens at mealtimes.
10. Some Medical Conditions Can Affect Weight
Certain medical conditions can make maintaining or losing weight more difficult.
The NHS lists conditions including an underactive thyroid and Cushing's syndrome among possible contributors to weight gain.
Mobility problems and other conditions that reduce someone's ability to be physically active can also have an effect.
This is one reason weight management should be considered individually rather than assuming everybody will respond in exactly the same way.
If you experience unexplained changes in your weight or are concerned that a medical condition may be affecting it, speak to an appropriate healthcare professional.
11. Some Medicines Can Affect Weight
Medication can sometimes influence appetite, activity or body weight.
The NHS notes that medicines including some:
- Steroids
- Antidepressants
- Beta blockers
can make maintaining a healthy weight more difficult for some people.
You should not stop prescribed medication because you believe it is affecting your weight.
If you are concerned about a medicine, discuss it with your doctor, pharmacist or prescribing clinician.
12. Appetite Is Not the Same for Everyone
Some people naturally think about food more frequently or experience stronger hunger signals than others.
That can make maintaining a reduced-calorie diet considerably harder.
This is also one reason modern weight management treatment increasingly recognises obesity as more complicated than simply telling someone to "eat less and move more".
Dietary habits and physical activity remain important, but biological differences between individuals matter too.
13. Weight Loss Medication Can Produce Different Results
Prescription weight management treatments can help some eligible adults with weight loss, but results still vary considerably between individuals.
Two people using the same treatment may not:
- Lose the same amount of weight
- Notice appetite changes at the same time
- Progress at the same rate
- Respond identically to treatment
Medicines used for weight management in the UK include options such as tirzepatide, semaglutide and orlistat. NICE recommends that weight management medicines are used alongside dietary changes and increased physical activity.
Medication should therefore not be viewed as a guaranteed way to lose a particular number of kilograms within a particular number of weeks.
Treatment always needs to be assessed individually.
Why Has My Weight Loss Slowed Down?
It is common for weight loss to be faster initially and then become slower.
As you lose weight, your body becomes smaller.
A smaller body generally requires less energy to maintain than a larger one.
Your routines may also gradually change.
Portions can become slightly larger, exercise can become less frequent or small habits can creep back in without being particularly obvious.
This can result in a period where your weight changes very little.
A weight loss plateau does not necessarily mean that your approach has completely stopped working.
Looking at your diet, activity, measurements and overall progress over several weeks can be more useful than reacting to a few days on the scales.
Is Fast Weight Loss Better?
Not necessarily.
Seeing the scales fall rapidly can feel encouraging, but faster does not automatically mean better.
Very restrictive diets can be difficult to maintain.
NICE advises against extreme dietary or physical activity behaviours that are difficult to sustain and recommends an individualised, nutritionally balanced approach to weight management.
The aim is not simply to produce the biggest possible number on the scales this week.
For most people, the bigger challenge is finding an approach that can be maintained.
Stop Comparing Your Week Two With Someone Else's Week Two
Weight loss is highly individual.
Someone on social media saying they lost a stone in a few weeks tells you very little about what you should expect.
You probably do not know their:
- Starting weight
- Height
- Medical history
- Body composition
- Activity level
- Diet
- Medication
- Previous weight changes
You are effectively comparing two completely different bodies.
Your own trend is far more useful.
How Should You Measure Weight Loss Progress?
The scales can be useful, but they are not the only measurement.
You might also notice:
- A smaller waist measurement
- Clothes fitting differently
- Improved mobility
- Increased activity levels
- Changes in appetite
- Changes in body shape
- Progress photographs looking different
NICE suggests that monitoring measurements such as weight and waist circumference can be useful for adults where appropriate.
Looking at several indicators can provide a better picture than allowing one number on the scales to determine whether you think you are succeeding.
Can Keltoi Help With Weight Loss?
For some adults, prescription weight management treatment may be an option alongside changes to diet and physical activity.
Keltoi provides online weight management assessments for adults considering prescription treatment.
You can complete your assessment online and your information is reviewed by a UK prescriber.
Your medical history, weight, BMI, current medication and other relevant information are considered before any prescribing decision is made.
If treatment is clinically appropriate, the available options can then be considered based on your individual circumstances.
All prescription treatment is subject to clinical assessment and suitability.
Frequently Asked Questions
Why am I losing weight slower than everyone else?
There may be many reasons, including differences in starting weight, body composition, activity, calorie intake, genetics, sleep, age, hormones, health conditions and medication. Comparing your progress directly with somebody else's is rarely useful.
Does having a slow metabolism make it harder to lose weight?
Energy expenditure varies between people, but metabolism is only one part of the picture. Body size, muscle mass, physical activity, food intake and other biological and lifestyle factors all contribute.
Why did I lose lots of weight in my first week?
Early changes on the scales can include changes in water and the amount of food in your digestive system, as well as changes in body fat. The first week should not necessarily be used to predict how quickly you will continue losing weight.
Why am I losing inches but not weight?
Changes in water, body composition and normal day-to-day weight fluctuations can sometimes mean that your measurements change even when the number on the scales moves very little.
Do heavier people lose weight faster?
They may lose more pounds or kilograms in absolute terms, particularly at the beginning. Comparing percentage weight loss rather than simply kilograms can give a more useful comparison.
Why has my weight stopped going down?
Weight loss does not normally happen in a perfectly straight line. Your energy needs, activity, eating habits and normal weight fluctuations can all contribute to periods where the scales appear to stop moving.
Does weight loss medication work at the same speed for everyone?
No. Individual responses vary. Prescription weight management treatments should be used following clinical assessment, and one person's results should not be treated as a prediction of somebody else's.
The Bottom Line
Some people lose weight faster than others because our bodies, lifestyles and circumstances are different.
Starting weight, genetics, body composition, age, hormones, physical activity, sleep, medical conditions, medicines and appetite can all influence progress.
So if your friend has lost more weight than you in the same amount of time, it does not automatically mean that your own approach is failing.
Look at your progress over time rather than comparing yourself with somebody else's results.
And if you are struggling to manage your weight despite making changes, there may be additional support available.
If you would like to find out whether prescription weight management treatment may be suitable for you, you can complete Keltoi's online eligibility assessment.