How to Lose Belly Fat: A Dietitian's Honest Guide
"How do I lose belly fat?" is something I'm asked almost every week in clinic. Usually it comes with a sigh, and a story about hundreds of crunches, a "flat tummy" tea or a plan that promised a smaller waist in seven days. If that sounds familiar, you're not doing anything wrong. You've just been sold the wrong tools.
As a Registered Dietitian specialising in weight management, I want to give you the honest version: what the evidence says about how to lose belly fat, why the quick fixes don't work, and the realistic changes that do.
Why does belly fat matter?
There are two main types of fat around your middle. Subcutaneous fat sits just under the skin (the bit you can pinch). Visceral fat sits deeper, around your organs.
Carrying more fat around your middle is linked to a higher risk of type 2 diabetes, high blood pressure and heart disease (NICE, 2025). That's why the UK's National Institute for Health and Care Excellence (NICE) now recommends measuring your waist as well as checking your BMI.
How do I know if I have too much belly fat?
You can check this at home with a tape measure and a calculator (NICE, 2025):
Find the bottom of your ribs and the top of your hips.
Measure around your waist halfway between the two, after breathing out naturally.
Divide your waist measurement by your height, using the same units for both.
A waist-to-height ratio of 0.4 to 0.49 is in the healthy range. A ratio of 0.5 to 0.59 suggests increased health risks, and 0.6 or more suggests further increased risks. Put simply, NICE advises trying to keep your waist to less than half your height (NICE, 2025). This measure is used for adults with a BMI under 35.
I like this measure because it moves the focus away from the number on the scales and towards your health.
Can you lose belly fat with exercises like crunches?
Unfortunately, no. The idea that you can "spot reduce" fat from one area by working the muscles underneath is one of the most persistent fitness myths.
In one randomised controlled trial, adults did seven abdominal exercises, five days a week, for six weeks. Their abdominal muscles got stronger, but there was no significant change in their abdominal fat, waist measurement or skinfolds compared with the group that didn't exercise (Vispute et al., 2011). It was a small study, but it fits with what we see in practice: crunches build strong muscles, they just don't burn the fat on top of them.
Strong core muscles are still worth having. They just aren't the route to a smaller waist on their own.
How to lose belly fat: what actually works
There's no special belly fat diet. Your body decides where it loses fat from, and the fat around your middle tends to go down as your overall body fat goes down. The good news is that the visceral fat around your organs responds well to the right changes.
1. Move more, in any way you enjoy
A large review of 40 randomised controlled trials, involving 2,190 adults living with overweight or obesity, found that exercise reduced visceral fat. The more energy people used through exercise, the bigger the effect (Recchia et al., 2023).
That doesn't mean you need to live in the gym. The NHS recommends adults aim for at least 150 minutes of moderate activity a week (or 75 minutes of vigorous activity), plus strengthening activities on at least 2 days a week (NHS, 2024). Brisk walking, cycling, swimming, dancing, a group class or a game of tennis all count. Personally, tennis and group exercise classes are what keep me moving, because I actually look forward to them. The best exercise is the one you'll keep doing.
2. Eat in a way that gently reduces your overall intake
The same review found that reducing calories also reduced visceral fat (Recchia et al., 2023). Interestingly, bigger cuts didn't lead to bigger reductions in visceral fat. That's a helpful reminder that extreme diets aren't the answer.
What I suggest instead:
Build meals around protein and vegetables. Eggs, beans, lentils, tofu, fish, chicken or Greek yoghurt, with a generous portion of veg or salad.
Choose higher-fibre carbs. Wholegrain bread, oats, potatoes with skins, brown rice and pulses. Adults in the UK are advised to aim for 30g of fibre a day, and average intakes are well below this (SACN, 2015).
Keep the foods you love. Pizza night and a curry with friends can still be part of the week. Plans that ban foods rarely last.
Notice your drinks. Alcohol, fancy coffees and fizzy drinks can quietly add up.
If you've been cutting back and nothing seems to be changing, my blog on why you might not be losing weight explains the most common reasons I see.
3. Protect your sleep
Sleep is easy to overlook, but it matters. In a small, carefully controlled study, healthy adults whose sleep was restricted to four hours a night for two weeks ate more calories and gained more fat around the middle, including visceral fat, than when they slept normally (Covassin et al., 2022). The study only included 12 people, mostly men, so we need more research. Even so, regular, good-quality sleep is a sensible part of any plan.
As a new mum, I know that "just get more sleep" isn't always possible. If your nights are broken, focus on the things you can control, such as regular meals and getting outside for a walk. My guide to losing baby weight has more ideas for tired parents.
4. Be patient and measure the right things
Fat loss from your middle happens gradually. Instead of weighing yourself every day, try measuring your waist every two to four weeks, noticing how your clothes fit, and tracking how you feel. These changes often show up before the scales move.
Why is belly fat harder to lose during the menopause?
If you're in your 40s or 50s and your waist has changed even though your eating hasn't, you're not imagining it. A large US study that followed women through the menopause found that the rate of fat gain doubled and lean (muscle) mass started to fall at the start of the menopause transition. These changes continued until around two years after the final period (Greendale et al., 2019).
This doesn't mean weight gain is inevitable. It does mean that strength training, enough protein and regular activity become even more important. If this is you, my page on diet and the menopause explains how I can help.
Not sure where to start?
Losing belly fat isn't about doing more crunches or cutting out food groups. It's about small, steady changes you can live with.
If you've lost weight before and it keeps creeping back, start with my free 5-Minute Weight Loss Audit. It helps you spot what's getting in your way, in just five minutes.
Or, if you'd like a plan that fits your life, you can book a free discovery call or find out how I help with weight loss.
No detoxes. No fad diets. No shame.
Frequently asked questions
What is the fastest way to lose belly fat?
There's no safe shortcut. Regular activity and a sustainable reduction in what you eat both reduce visceral fat, and bigger calorie cuts don't seem to bring bigger reductions (Recchia et al., 2023). Steady changes you can keep up are the way to go.
Do sit-ups burn belly fat?
No. Sit-ups and crunches strengthen your abdominal muscles, but research shows they don't reduce the fat around your middle on their own (Vispute et al., 2011).
What should my waist measurement be?
NICE recommends keeping your waist to less than half your height. A waist-to-height ratio of 0.5 or more suggests increased health risks (NICE, 2025).
Can poor sleep cause belly fat?
Short sleep has been linked to more fat around the middle in a small controlled study (Covassin et al., 2022). Looking after your sleep is a sensible step, alongside eating well and staying active.
Why do I gain weight around my tummy in the menopause?
The menopause transition is linked to faster fat gain and a loss of muscle (Greendale et al., 2019). Staying active, including strength training, can help.
This article is general information and does not replace individual advice from your GP or a Registered Dietitian.
About the author
Caroline Bletcher is an HCPC Registered Dietitian (DT29447) specialising in weight management, with more than 10 years' experience in the NHS and private practice. She supports clients in Surrey and online.
Covassin, N., Singh, P., McCrady-Spitzer, S.K., St Louis, E.K., Calvin, A.D., Levine, J.A. and Somers, V.K. (2022) 'Effects of experimental sleep restriction on energy intake, energy expenditure, and visceral obesity', Journal of the American College of Cardiology, 79(13), pp. 1254–1265. Available at: https://doi.org/10.1016/j.jacc.2022.01.038
Greendale, G.A., Sternfeld, B., Huang, M., Han, W., Karvonen-Gutierrez, C., Ruppert, K., Cauley, J.A., Finkelstein, J.S., Jiang, S.-F. and Karlamangla, A.S. (2019) 'Changes in body composition and weight during the menopause transition', JCI Insight, 4(5), e124865. Available at: https://doi.org/10.1172/jci.insight.124865
NHS (2024) Physical activity guidelines for adults aged 19 to 64. Available at: https://www.nhs.uk/live-well/exercise/physical-activity-guidelines-for-adults-aged-19-to-64/ (Accessed: 27 October 2026).
NICE (2025) Overweight and obesity management (NICE guideline NG246). Available at: https://www.nice.org.uk/guidance/ng246 (Accessed: 27 October 2026).
Recchia, F., Leung, C.K., Yu, A.P., Leung, W., Yu, D.J., Fong, D.Y., Montero, D., Lee, C.-H., Wong, S.H.S. and Siu, P.M. (2023) 'Dose–response effects of exercise and caloric restriction on visceral adiposity in overweight and obese adults: a systematic review and meta-analysis of randomised controlled trials', British Journal of Sports Medicine, 57(16), p. 1035. Available at: https://doi.org/10.1136/bjsports-2022-106304
Scientific Advisory Committee on Nutrition (SACN) (2015) Carbohydrates and Health. London: TSO. Available at: https://assets.publishing.service.gov.uk/media/5a7f7cc3ed915d74e622ac2a/SACN_Carbohydrates_and_Health.pdf (Accessed: 27 October 2026).
Vispute, S.S., Smith, J.D., LeCheminant, J.D. and Hurley, K.S. (2011) 'The effect of abdominal exercise on abdominal fat', Journal of Strength and Conditioning Research, 25(9), pp. 2559–2564. Available at: https://doi.org/10.1519/JSC.0b013e3181fb4a46
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