How do I work out my weight loss percentage?
Weight lost ÷ starting weight × 100. So 6 kg off 90 kg is 6.7%. On a weight loss jab? On the NHS, one percentage helps decide whether you carry on.
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How do I work out my weight loss percentage?
Take your weight now from your starting weight. Divide what you’ve lost by your starting weight. Then times by 100.
Say you started at 90 kg and now weigh 84 kg. You’ve lost 6 kg. 6 ÷ 90 = 0.067, and × 100 gives 6.7%.
Weigh in stone? Turn both weights into pounds first, with 14 lb in a stone. From 15 st (210 lb) down to 14 st (196 lb) is 14 lb, or 6.7%.
| Starting weight | 5% is | 10% is |
|---|---|---|
| 70 kg | 3.5 kg | 7 kg |
| 80 kg | 4 kg | 8 kg |
| 90 kg | 4.5 kg | 9 kg |
| 100 kg | 5 kg | 10 kg |
| 110 kg | 5.5 kg | 11 kg |
| 12 st (168 lb) | 8.4 lb | 16.8 lb |
| 15 st (210 lb) | 10.5 lb | 21 lb |
| 18 st (252 lb) | 12.6 lb | 25.2 lb |
Always divide by where you started, not where you are now. Find your row and write down your 5% number. That’s your first goal.
Is 5% weight loss good?
Yes. The NHS says losing 5 to 10% of your body weight can improve your health. That’s 4.5 to 9 kg if you started at 90 kg.
- Below 5 %Under the 5% NICE uses to check jabs.
- 5 to just under 10 %NHS: can improve your health.
- 10 % or above10 to 15%: bigger gains in one large diabetes study.
Sources: NHS; NICE TA875; Look AHEAD
More can help more. A study of 5,145 adults with type 2 diabetes and extra weight tracked them for a year.
Losing 5 to under 10% was linked to better blood sugar, blood pressure and blood fats. Those who lost 10 to 15% were even more likely to improve on most of these. LDL cholesterol, the kind the NHS calls bad cholesterol, was the exception: it didn’t track weight loss.
To see where your new weight sits, check your BMI number or your healthy weight for your height.
What percentage do weight loss jabs need?
The number is 5%. NICE, which sets NHS treatment rules, uses it to judge whether a weight loss medicine is working well enough to keep going on the NHS.
| Medicine | When it’s checked | If you’ve lost under 5% |
|---|---|---|
| Tirzepatide (Mounjaro) | After 6 months on the highest dose that suits you | Decide together whether to carry on. |
| Semaglutide (Wegovy) | After 6 months | Think about stopping. |
| Liraglutide | After 12 weeks on 3.0 mg a day | Stop. |
| Orlistat | After 12 weeks | Stop. |
Sources: NICE TA1026; NICE TA875; NICE NG246; NHS
On tirzepatide, it isn’t an automatic stop. NICE says to weigh up the benefits and risks for you. On semaglutide, NICE says to consider stopping.
Wegovy is the brand of semaglutide used for weight. Work out your % from the weight on your first day, and bring it to your review.
Never stop or change a prescribed medicine without your prescriber. For checks on these medicines, see blood tests on Mounjaro and blood tests on Wegovy.
How fast should I lose weight?
Steadily. The NHS says aim for 0.5 to 1 kg, or 1 to 2 lb, a week.
At 100 kg, 5% is 5 kg. At that pace, it takes 5 to 10 weeks.
Track your percentage the same way each time
- 1
Day one
Write down your starting weight. Every % uses it.
- 2
Check in
Weigh yourself regularly to check how you’re doing.
- 3
Weigh regularly
Work out your % from your starting weight each time.
- 4
Steady pace
Aim for 0.5 to 1 kg a week.
Source: NHS
One weigh-in is a photo, not a film. Judge your % over a few weeks, not one morning.
How do I keep losing?
Six NHS steps to reach your next 5%
- Eat and drink fewer calories than your body uses.
- Cut down on high fat or sugary foods, and eat plenty of fruit and vegetables.
- Cut down on alcohol, which is high in calories.
- Get active for 45 to 60 minutes a day. You can split it into shorter bouts.
- Try a free plan such as Couch to 5K.
- Set realistic goals and weigh yourself regularly to check how you’re doing.
Source: NHS: overweight and obesity
Keeping it off can take more. NICE says people who lived with obesity and lost weight may need 60 to 90 minutes of activity a day to avoid regaining it.
For ideas, see walking to lose weight, keeping muscle as you lose weight and weight loss programmes.
When to speak to a GP
Losing weight without trying? See a GP if you keep losing weight without changing your diet or exercise. Go as soon as possible if you have other symptoms too.
Is your BMI in the overweight or obese range? The NHS also says see a GP if:
- you want help to lose weight
- your waist is more than half your height (see waist to height ratio)
- you have pre-diabetes, diabetes, high blood pressure, joint pain, high cholesterol, sleep apnoea or heart or circulation disease
- obesity runs in your family
- you have, or think you may have, an eating disorder, such as binge eating
Sleep apnoea is when your breathing stops and starts while you sleep. On a weight loss jab and under 5% at your review? Talk it through with your prescriber.