Why are thin people not fat? Horizon documentary on BBC2 at 9 this evening

I used to be one of these people who was skinny as air and ate junk without seemingly putting weight on. I have largely (excuse the pun) blamed my transormation into a semi tubby on having two kids then turning 30. However, in my twenties although I ate crap sometimes I also went several nights a week not eating because I was too busy out drinking. I also used to jog a lot and dance most of my weekends away. So skinny, but not a picture of health. Nowadys I simply do not do enough excercise and often eat rather rich food. I'm not an elephant, but I am unhappy with my size.

As a former fat person, I will be watching this with interest <shoves another cheese scone in gob>

Did you see the news report earlier - apparently there's a new train of thought that links obesity to having had a certain cold / flu virus (can't remember which sorry) which makes fat cells replicate

http://news.bbc.co.uk/2/hi/health/7851031.stm

As a former skinny person, its because they don't eat much. they might tell you they eat like a horse, you might see them eats tons- but they won't be doing it all the time (if I'd eaten loads at night I'd often not eat until the next evening) and their idea of eating like a horse will be very different from a fat persons. I didn't know it was possible to eat so much until i stopped being naturally skinny.

Its not consious, its just why they are skinny.

now i want some more food.

There have been al kinds of studies over the years about what makes human beings lay down more fat cells than average. In some case I am sure that some poeple are more predisposed to putting on weight. However, getting to a state of obesity is surely only attained by eating too much and not excercising the extra calories off

There was a magazine article on the BBC website with some interesting studies:

http://news.bbc.co.uk/2/hi/uk_news/magazine/7838668.stm

I think it's probably a mixture of genetics and lifestyle. Despite running 4/5 times per week, I still can't trough pies and drink pints of beer every day without putting on weight.

Then perhaps the age things comes in. Are you over thirty, Baron?

Yes ?

Then again, up until last year I was a massive porker and had always been overweight apart from a brief spell when I was 17/18 and lost a little weight (still weighed more then than I do now).

Hyacinth - that's why I'm going to be watching this with interest.

They did a study with ?10/20 skinny volunteers and made them double their calorie intake for a month.

I don't know the results (can't find them online) but from the TV reviews it's not as simple as they all put weight on....

Well I do think that being over thirty doesn't help <sob>

What really annoys me is that when I was skinny I never even appreciated that I had a decent figure. I had a face from Crimewatch but definately a body from Baywatch ?

Well, if the summary if this is that fat people are fat because of genetics, then I'll probably cry. I need some hope that there's a chance of getting a smaller bum.

This is hugely depressing so far - it seems either my body is destined to try to keep me at 'a certain weight' or I am never ever going to be one of those people that can eat four million calories a day and be skinny. Oh and 'chocolate is very dangerous'

I think I might turn this off and watch paul Mckenna instead.....

Didn't see it, might watch on iplayer... anyway, being 30+ and giving up smoking has definitely been A Very Bad Thing for my size, and my ability to lose weight.

Absolutely what PL said re giving up smoking and being over 30. I was fairly slim when I was a young smoker. Now I am old and nicotine free, I am also much, much bigger despite going from a sedentary lifestyle as a work-from-home PA to a run-around-like-a-headless-chicken chef and taking up running. Pah.

That settles it, I'm not giving up smoking ?

There was a bit where they said we have to control our daily calorie intake by +/- 7 calories to have any real influence on our weight. How utterly depressing (although not sure I'm convinced).

I thought this was very interesting...

I notice that out of the 10 volunteers, there was one person who appeared to put on muscle rather than fat - that has to be genetic. There were some people who just got fatter, a couple of people who were physically unable to eat the target number of calories, and two people who ate all the food but didn't put weight on - they think those people just increased their physical activity by fidgetting more.

I think it makes sense that some people seem to have a 'natural' weight. Mine seems to be in the 'overweight' range, as I was doing WW for about a year and managed to gain and lose the same 5lb over and over again - and when I gave up WW and just ate what I wanted, I stayed the same weight.

Seven calories a day? That would mean a difference of less than a pound a year.

That was the point. Most people seem to maintain a fairly constant weight throughout their lives. If they were doing this by regulating what they eat, the would only be able to vary their daily intake by +/- 7 calories - obviously, this is extremely unlikely, so there must be some other mechanism for regulating weight.

Couldn't agree more, MrsJess, I know it was my fault for putting the weight on in the first place- I always say that I gave up cigarettes and took up crisps- but my problems now lie with shifting the excess weight. I have joined a gym, taken up running and switched jobs since giving up in July 07 and still weigh far too much. Not blaming the cigs per se- just finding it very difficult to lose weight and sometimes, very secretly, wish I hadn't stopped.

Okay, I see what you mean. That's just not so though - unless I'm still missing the point? I think what "naturally" slim people do is vary their calorie intake by up to several hundren calories a day, but over time it averages out?

It's obviously also not true that every slim person has an identical calorie intake. There's a big variation in how many calories people need, obviously, depending on their size, activity level and so on.

I've just started a course of hypnotherapy/counselling to try and get the bottom of my eating habits. Amongst other things, I'm being taught how to eat like a thin person and it's quite hard to get my head round that after 10+ years of eating like a fat person. I've amazed myself with how much less I am eating just by only eating when I am hungry (sounds obvious but I'm a stickler for routine) and stopping when I'm not hungry (which is very different to being full). I'm now fascinated by watching the eating habits of my thin friends and am starting to understand why I am fat.

That's true - people don't eat the same amount of food every day, and naturally slim people tend to not eat so much the day before or after a day when they've eaten a lot. Must learn how to do that.

Yep, that was the point; that to maintain a constant body weight throughout adult life (as apparently most people do) you need to eat - on average - no more or less than 7 cals a day than you need.

The point was, this is nearly impossible for a human to do consciously - so they were trying to suggest ways the bodies of 'naturally slim people' do it unconsciously.

E.g. excessive fidgetting, strong nausea/satiety response to overeating - and there was one guy who laid on all the extra weight as muscle - thereby increasing his BMR by 30%.

All unconscious, suggested ways that 'thin people's bodies try to keep them thin'.

Twas an interesting programme.

Mr G is a thin person and seems to eat lots, but whilst he'll eat loads for main meals he hardly ever snacks.

When I was thin (all those years ago) I was exercising and keeping busy so I didn't have time to snack. Now I don't exercise as much as I'm not as busy I'm a lot fatter!

Cheers R-A, that makes sense.