The Student Room Group

BMI...a guideline?

I've seen people say that BMI shouldn't be taken too seriously, it doesn't account for muscle or body composition.
But I've also seen people say that it can be a good indicator particularly in the underweight category.
I've always had a low BMI but have never felt unhealthy. Currently I swim three times a week, do other workouts twice and eat 3 good, nutritious meals a day plus 2-3 snacks and dessert.

18.5 is the lower boundary for being a healthy weight, anything below is considered underweight. On the left I am 115lbs at 5 ft 6 with a BMI of 18.6 (only just in the healthy range), on the right I am 105lbs with a BMI of 16.9. Now 16.9 is supposedly ridiculously underweight but I don't feel or think I look too thin. I'm 20 so shouldn't be using the childs BMI tools, but do I need to gain weight? I'm happy with my body but BMI says I'm unhealthy

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BMI tends to be more of a guide then anything else, and from what you say you seem to have a healthy lifestyle but - important but - if you don’t feel sure the best answer is always to ask a doctor!
Reply 2
Original post by Anonymous
I've seen people say that BMI shouldn't be taken too seriously, it doesn't account for muscle or body composition.
But I've also seen people say that it can be a good indicator particularly in the underweight category.
I've always had a low BMI but have never felt unhealthy. Currently I swim three times a week, do other workouts twice and eat 3 good, nutritious meals a day plus 2-3 snacks and dessert.

18.5 is the lower boundary for being a healthy weight, anything below is considered underweight. On the left I am 115lbs at 5 ft 6 with a BMI of 18.6 (only just in the healthy range), on the right I am 105lbs with a BMI of 16.9. Now 16.9 is supposedly ridiculously underweight but I don't feel or think I look too thin. I'm 20 so shouldn't be using the childs BMI tools, but do I need to gain weight? I'm happy with my body but BMI says I'm unhealthy

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BMI is only a guideline and can't be too accurate cos it doesn't know how much of you is fat or muscle (they weigh different amounts).
If it's saying you're ridiculously underweight though and you are sure you've used the right measurements it's probably worth checking with a doc. BMI shouldn't be so inaccurate that it's shoving you an an extreme of the wrong category.
Go onto the NHS BMI checker, make sure you're using your age and sex and the right measurements then see what it says. If it's still saying you're really underweight it might be worth checking with a doctor.

Hope that helps.
3 good, nutritious meals a day plus 2-3 snacks and dessert. just to be clear what do you actually eat.
BMI is a very weak indicator of health. If you feel healthy, odds are that you're healthy.
It's very inaccurate as it doesn't take into account muscle mass. Think of those big powerful rugby players like Billy Vunipola or Tadgh Furlong who weigh 120-130kg, every BMI calculator will show them as obese when it's clearly not the case.
Reply 6
Original post by paulbarlow
3 good, nutritious meals a day plus 2-3 snacks and dessert. just to be clear what do you actually eat.


Something like

Breakfast- bowl of porridge with berries and honey

Lunch- pastrami and mustard sandwich on seeded bread, a yoghurt, packet of savoury snacks (like pea snacks from ALDI which are like flavoured baked pea pods) and fruit such as grapes or a plum. Occasionally a cake bar if I have them in

Dinner- Honey glazed salmon fillet with lemon and coriander cous cous and green veg medley

Dessert- some flavour of ice cream

Snacks- more fruit, a seed-nut-dried fruit medley, a couple of biscuits with a cup of tea
Original post by Anonymous
I've seen people say that BMI shouldn't be taken too seriously, it doesn't account for muscle or body composition.
But I've also seen people say that it can be a good indicator particularly in the underweight category.
I've always had a low BMI but have never felt unhealthy. Currently I swim three times a week, do other workouts twice and eat 3 good, nutritious meals a day plus 2-3 snacks and dessert.

18.5 is the lower boundary for being a healthy weight, anything below is considered underweight. On the left I am 115lbs at 5 ft 6 with a BMI of 18.6 (only just in the healthy range), on the right I am 105lbs with a BMI of 16.9. Now 16.9 is supposedly ridiculously underweight but I don't feel or think I look too thin. I'm 20 so shouldn't be using the childs BMI tools, but do I need to gain weight? I'm happy with my body but BMI says I'm unhealthy

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don't waste a doctors time with this, a couple of people are actually recommending that which really shocks me
If you feel fine then why are you worrying? you seem to have a healthy lifestyle, if ur happy with ur body who cares if your in the underweight category
Original post by Anonymous
Something like

Breakfast- bowl of porridge with berries and honey

Lunch- pastrami and mustard sandwich on seeded bread, a yoghurt, packet of savoury snacks (like pea snacks from ALDI which are like flavoured baked pea pods) and fruit such as grapes or a plum. Occasionally a cake bar if I have them in

Dinner- Honey glazed salmon fillet with lemon and coriander cous cous and green veg medley

Dessert- some flavour of ice cream

Snacks- more fruit, a seed-nut-dried fruit medley, a couple of biscuits with a cup of tea
seems a decent menu. if thats your normal food who can say why your skinny. i wish i had that problem. just make sure you dont lose more.
How much do you eat? If you're swimming 3 times a week plus other workouts you should be eating more than an average person.
Original post by Student-95
How much do you eat? If you're swimming 3 times a week plus other workouts you should be eating more than an average person.


I posted an average menu above but when I come in from a swim or workout I usually have a protein bar and high protein yogurt such as greek style or a bowl of Skyr with fruit
Original post by Anonymous
I posted an average menu above but when I come in from a swim or workout I usually have a protein bar and high protein yogurt such as greek style or a bowl of Skyr with fruit


How many calories? Listing a bunch of food doesn't really tell us much.
Original post by Student-95
How many calories? Listing a bunch of food doesn't really tell us much.


Breakfast comes to around 350 for the porridge
Lunch around 500 for the packed lunch style
My dinners can range from 500-700
If my daily snacks were to be some trail mix, a crumpet with butter and three biscuits then that's about 400-450

That alone is 1750-2000 calories, not including calories from cooking oils (which I don't measure, I just use as much as I need) or drinks or the protein bars on days I eat them which are about 160-180 each I think

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