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Can you be underweight and fat?

42 replies

galaxyfaraways · 28/07/2026 22:21

I have a bmi of 18.1 but look physically fat, my stomach patrudes and is flabby so I can make several rolls from it and if I put on a dress I look pregnant.
I see people walk around with their stomach showing and I could never look like that but apparently I’m under weight?

OP posts:
Likeiloveyou · 29/07/2026 07:49

I think this is just the result of having four children. I am sure they are worth it.

galaxyfaraways · 29/07/2026 07:49

Denim4ever · 28/07/2026 23:50

Agree, size 6 is for teenagers. It's very small

Size 6 is for people who are size 6 like any size, lots of women are size 6 it’s not nice comparing them to children.

OP posts:
Culpeper · 29/07/2026 07:55

I’m very slim, my body fat is a respectable 22% - but my lower abdomen is horribly flabby and needs toning. If I lie on my side it flops over.

Crumpetring · 29/07/2026 08:02

I think OP it would be more accurate to say that it is entirely plausible to be a size 6, have a BMI of 18 but also not have a flat stomach.

Very few women actually do have a flat stomach. I would imagine after 4 children it would be quite unlikely. Your muscles will work slightly differently, your uterus may be slightly larger and age causes women to carry weight in different places.

I read in a book once that the evolutionary reasons why flat stomachs are seen as attractive is because before birth control it could be associated with virginity. Having a mate that was a virgin would give a male more parental certainty that it would be his genes that would continue. I mean evolutionary reason as in cave man times. But it’s why human brains find flat stomachs attractive today.

WhereAreWeNow · 29/07/2026 08:03

galaxyfaraways · 29/07/2026 07:33

No. I walk to work about 20 mins each way though.

40 mins walking is not a lot of physical activity. It sounds like you're not fat but you don't have strong core muscles. Have you tried doing some ab exercises at home? Caroline Girvan or Mad Fit or any of the free workouts on YouTube? I suspect you'll see changes in your core strength and tone quite quickly.

PeterRabbitsWhiskers · 29/07/2026 08:07

Denim4ever · 28/07/2026 23:50

Agree, size 6 is for teenagers. It's very small

Can you stop this please? Size 6 is a perfectly normal size for a petite adult woman. It may be smaller than average but is is so demeaning to call it teenage size, teeny tiny etc. Now, in my 50s, I have reached an 8-10 having been a 6 all my life.

charactershoes · 29/07/2026 08:11

If you’re a bit flabby in the stomach area then this is totally normal especially if you’ve had children.

Is your belly actually protruding though? If so then if you’re very slim everywhere else then I think it’s worth mentioning to the GP as this can be a sign of health issues.

RoseField1 · 29/07/2026 08:12

Culpeper · 29/07/2026 07:55

I’m very slim, my body fat is a respectable 22% - but my lower abdomen is horribly flabby and needs toning. If I lie on my side it flops over.

Toning doesn't really exist. Even if you developed rock hard abs if you've got fat on your abdomen it's still going to flop. Sorry!

Gonnaeatalotofpeaches · 29/07/2026 08:31

@RoseField1 if their is more muscle it will hep though. After my second baby my tummy was wobbly because the muscle were lax and not holding everything in tightly. I still have a bit of fat on my lower abdomen but it’s much more taught than when my muscles weren’t doing their job. My bmi is also about 18.5 so similar to op and a similar height too.

Justaquestionplease · 29/07/2026 08:34

Fat is a silly word in this context. We all have fat on our bodies... we'd be in a whole load of trouble if we had zero fat. Most of us can make rolls with our belly even if we are thin and underweight....it's just skin and you know being a human being. But no you're not overweight so you won't look overweight.

Mumtobabyhavoc · 29/07/2026 08:38

You likely lack muscle. That's an easy fix.

MyDarlingRose · 29/07/2026 08:43

That depends on what fat means to you.

You could be underweight but have a low muscle mass to body fat percentage aka unfit but you can’t be overweight (which is usually what people mean by fat).

Either way it’s not safe for you to lose more weight - I’d actually propose you GAIN weight and use weight lifting/strength training to add muscle to your frame.

MyDarlingRose · 29/07/2026 08:48

Denim4ever · 28/07/2026 23:50

Agree, size 6 is for teenagers. It's very small

It’s really not. Many of us are short. I am 5’3 and BMI 20 and a 6-8. My waist is 26inches which isn’t that small. People have just forgotten what a healthy weight range is for many petite people (generally a 6-10, I was BMI 27 at a 12).

BogRollBOGOF · 29/07/2026 08:55

galaxyfaraways · 29/07/2026 07:37

I do need to work on my posture, I have quite a curved spine like my mum and she looks quite hunched now at 80 and I definitely feel like I’m getting shorter.

Most likely you need to build muscle strength, particularly in the core. The walking is a decent level for cardiovascular health, but building and maintaining muscle mass is essential for health and mobility in older age.

If you're of a naturally petite build, you may not build much volume of muscle mass, but size isn't an indicator of strength. It would help balance your limb/ body proportions from an aesthetic point of view as well as the long term benefits. Taking up resistance/ weights, and having a good proportion of protein in your diet, and adding a creatine supplement (also beneficial for brain health) is an effective combination.

Presumably with a mum at 80, you're in middle age where hormone changes do increase fat storage on the abodomen, and skin becomes less taut. You won't be "fat" though, but under-muscled is not good for long term health.

BillieWiper · 29/07/2026 09:16

Just do some ab and core strengthening exercises. Walking for 40 minutes a day is virtually no exercise at all. But I think most people would be happy with being a size six even if their belly was a bit flabby!

Barryselection · 29/07/2026 09:35

Oh my goodness this is me!! I could have honestly written this. I am a size 8/10 with a normal/slightly lower BMI but my stomach is so flabby and I definitely look bigger than I am. I’ve only had one pregnancy but I was also wondering if it could be something to do with the muscles. I must say Pilates really helped me and I’ve started doing regular weight exercises but no matter how small I am a cannot get rid of excess fat around my stomach.

BauhausOfEliott · 29/07/2026 09:52

You can be underweight with a high body fat percentage, yes. Muscle is much denser than fat, so someone who is small and muscular will often weigh more than someone who is the same size but has very little muscle.

The solution isn’t to eat less. It’s to do some strength training and if you can, up your protein intake without cutting carbs.

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