Why is it harder to lose weight when you're lighter?

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savagenoble
savagenoble Posts: 8
in Health and Weight Loss
I've read repeatedly that the less you weigh, the harder it is to lose weight. But why is that? Even if your body is more efficient (i.e. can burn fewer calories doing the same work) when you're lighter, that doesn't seem to account for the fact that it is much, much more difficult to lose at lighter weights. Imagine two people who don't exercise at all and eat at a caloric deficit–could it really be that the heavier person's heartbeat, etc. takes so many more calories that the two people lose weight at drastically different rates? If that were the case, then shouldn't there be more of a balancing mechanism, where heavier people lose weight SO easily and lighter people GAIN weight so easily (because of how efficiently they do work with fewer calories) that it'd be hard for anyone to drastically gain or lose weight? Everyone would just sort of drift to some kind of equilibrium weight, where it's not easy to gain or to lose weight. Or am I completely wrong? Does anyone know any more about this?

Replies

  • BarackMeLikeAHurricane
    BarackMeLikeAHurricane Posts: 3,400 Member
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    When you're smaller you have lower maintenance calories and your body is more likely to adapt to a lower calorie diet by lowering the amount of energy it expends. When you're big you have much higher maintenance calories and your body has tons of energy stores so it doesn't worry about you starving to death. A big person's body knows it clearly has enough access to food so it's safe to expend extra energy.
  • albertabeefy
    albertabeefy Posts: 1,169 Member
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    When you're smaller you have lower maintenance calories and your body is more likely to adapt to a lower calorie diet by lowering the amount of energy it expends. When you're big you have much higher maintenance calories and your body has tons of energy stores so it doesn't worry about you starving to death. A big person's body knows it clearly has enough access to food so it's safe to expend extra energy.
    ^^ Bang on.
    I was about 350lbs at one point, and even with a whopping 2 minutes of exercise each day, weight poured off me as long as I stayed above by BMR.

    When I was around 320lbs and able to exercise over 1/2 an hour a day, I actually lost 70lbs in 3 months, retained the vast majority of what little lean mass I had (I experienced a lot of atrophy over a few years of bed rest), and was never hungry at all.

    Under 240lbs for me it slows down considerably unless I actually increase my caloric intake while simultaneously increasing my exercise calories in a 1:2 ratio. IE: I'll add 500 calories to my diet but burn 1,000 more.

    Sounds weird, but it works for me. The increase in caloric intake lets my body know I'm not starving, and the large increase in exercise expenditure creates a larger daily deficit than before, which = greater weight loss for me.

    If I don't have time to add the extra exercise in, obviously I don't eat the additional calories. I can't always find an extra hour each day for it.
  • Xiaolongbao
    Xiaolongbao Posts: 854 Member
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    The drifting to an equilibrium weight does happen for quite a lot of people BUT as people get heavier they also tend to move less which means that they can put on more than if they'd stayed at the same activity level.

    I've lost over 20kg. If I put on a 20kg backpack and walk up a few flights of stairs I can definitely tell how much more effort it is for my body and how many more calories I was burning when I was heavier. I walk up and down stairs all day at work. So yes, it's easy for me to believe my body is burning a LOT less calories now. Especially because that extra weight was on me for every little activity. Even sitting here typing.

    The other thing is that of course as you get closer to being an appropriate weight your body gets less and less keen to give up the weight. It will look for ways to be more efficient and burn less fat because it is "worried" that there are less stores left should hard times strike.
  • lagringaloca1
    lagringaloca1 Posts: 22 Member
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    I agree with the above poster. That's also why the calories burned while just walking around doing nothing more than your usual routine will be different at different weights as you are losing.
  • savagenoble
    savagenoble Posts: 8
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    Thanks for the replies, everyone! I still find it confusing that the body is not a strict calorie-in-calorie-out machine (in that it can decide how many calories to spend on the going-out end according to whether or not it thinks there is fat/energy to spare, etc.), but this helps elucidate some of that for me, especially in terms of efficiency in lean (ha!) times.
  • TavistockToad
    TavistockToad Posts: 35,719 Member
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    Thanks for the replies, everyone! I still find it confusing that the body is not a strict calorie-in-calorie-out machine (in that it can decide how many calories to spend on the going-out end according to whether or not it thinks there is fat/energy to spare, etc.), but this helps elucidate some of that for me, especially in terms of efficiency in lean (ha!) times.

    thats exactly the problem... the body is not a machine.... we have evolved over thousands of years, the body is very clever at staying alive and storing fuel so those of us who are getting rid of 'vanity pounds' really struggle!!
  • that1milestone
    that1milestone Posts: 3
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    It's all anatomy and physiology really. I like to think of the body as a machine, but I know that in technical terms it's not. Your body is so good at what it does that it adapts quite quickly to even the slightest changes in your environment, diet, etc. It's not like the human body has a calculator that sits there and does the math -- it's all about food quality and quantity.

    Some foods boost your metabolism that can help you lose weight, but generally when you get down to slimmer weights calories consumed doesn't play as large of a role as it does when you're heavier. Exercise is the new important factor. Like previous posters said, it takes less energy for your body to function when it's not being weighed down by fat.

    When you weigh more it takes more energy for even simple movements. For example if you're lifting weights it doesn't take much effort to lift a 20 lbs. weight, but it takes a lot of effort to lift a 60 lbs. weight. Imagine that your body is constantly lifting weights and it needs a ton of energy in order to lift those weights. So your body needs a lot more calories in order to function, but when you cut those calories down it has to turn to fat burning in order to continue working.

    It's not so much calories as it is how much energy you're consuming. It all comes down to glucose and ATP. The more your body needs the more fat it burns off when it doesn't get enough. When your body isn't constantly lugging around a ton of weight it doesn't need that much energy to make movements and if you're not exercising a lot then it needs even less energy.

    If you've only got 5-20 lbs. of fat on you it doesn't take a lot of effort for your body to keep up like it would if you had more, so it's not burning that excess weight. So if you're eating enough food to give your body energy then it's not going to burn off fat that it doesn't need. Your body is a very smart and it doesn't store fat for the fun of it! It stores fat for emergencies and it will burn off the fat only when it absolutely needs the fat for energy to function properly.
  • 257_Lag
    257_Lag Posts: 1,249 Member
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    Not scientific by any means but if I weight 100 lbs more than you do and we both walk one mile I burn more calories than you do. This goes from daily activities to full blown workouts.
  • khall86790
    khall86790 Posts: 1,100 Member
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    When you're smaller you have lower maintenance calories and your body is more likely to adapt to a lower calorie diet by lowering the amount of energy it expends. When you're big you have much higher maintenance calories and your body has tons of energy stores so it doesn't worry about you starving to death. A big person's body knows it clearly has enough access to food so it's safe to expend extra energy.

    Thanks for this. I have noticed since I hit my initial GW and gave myself a new to lose a final 5kgs before maintenance, it's been quite a slow process and it tends to fluctuate more (e.g. one day I will be 63kgs but 3-4 days later I am back to 64kgs).
    It's frustrating but it makes sense and I suppose in it's own way, it's a victory when you do get to this point.
  • watcheronthewall
    watcheronthewall Posts: 104
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    When you're smaller you have lower maintenance calories and your body is more likely to adapt to a lower calorie diet by lowering the amount of energy it expends. When you're big you have much higher maintenance calories and your body has tons of energy stores so it doesn't worry about you starving to death. A big person's body knows it clearly has enough access to food so it's safe to expend extra energy.
    ^^ Bang on.
    I was about 350lbs at one point, and even with a whopping 2 minutes of exercise each day, weight poured off me as long as I stayed above by BMR.

    When I was around 320lbs and able to exercise over 1/2 an hour a day, I actually lost 70lbs in 3 months, retained the vast majority of what little lean mass I had (I experienced a lot of atrophy over a few years of bed rest), and was never hungry at all.

    Under 240lbs for me it slows down considerably unless I actually increase my caloric intake while simultaneously increasing my exercise calories in a 1:2 ratio. IE: I'll add 500 calories to my diet but burn 1,000 more.

    Sounds weird, but it works for me. The increase in caloric intake lets my body know I'm not starving, and the large increase in exercise expenditure creates a larger daily deficit than before, which = greater weight loss for me.

    If I don't have time to add the extra exercise in, obviously I don't eat the additional calories. I can't always find an extra hour each day for it.

    Oooh this is very interesting and worth bearing in mind for me. I started at 261 and while weight has never poured off and weight loss hasn't dramatically slowed down as yet, it has lessened and I am preparing myself for it being much slower in the future.

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