What Does Science Say You Should Do Once You’ve Lost the Weight?

You’ve put a lot of hard work into losing weight, good for you! That’s a major accomplishment! Now you want to keep it off or even lose a little more. Here’s the thing there is emerging science that reveals that people who have lost a lot of body weight (aka those that are weight reduced) actually have bodies that function a little differently than those that have always maintained the same lower body weight. Now this does kinda suck because the weight reduced person has to work harder and probably eat less just to maintain that new weight. But … the fact that we’re starting to understand and quantify that is a great thing! This new research means that we now understand why people seem to always gain back the weight and they can now take steps to prevent it. In this post we’ll get into what it means to be weight restricted, why that’s not a bag thing and what the commonalities are for people who keep the weight off long term. In other good news those habits that help you keep the weight off are also a pretty good way to loose it in the first place.

What does it mean to be weight reduced?

Imagine two ladies, identical twins, Kelly and Laura both are 5’6”. A healthy weight range for these ladies is anywhere between 115 -155 pounds according to BMI calculations. Kelly has always maintained a weight of 140 pounds for her adult life other than during pregnancy and her weight hasn’t fluctuated much more than 10 pounds over her adult life. Laura on the other hand has generally been overweight and over 200 pounds for the last 10 years, now she weights 250 but she has decided to make some changes. Laura loses 110 pounds and now weights the same as her twin. Laura is now weight reduced while Kelly is not. In order to maintain a weight of 140 pounds we can calculate that these ladies need about 1600 calories a day if they are sedentary or 2000 if they are lightly active. The thing is we’re realizing that if Kelly eats that amount she’ll stay at 140 pounds while Laura will gain the weight back at about the rate of one pound a week. How is that fair? Well it’s not and no one said biology is fair!

We used to assume that every body acts the same and that it’s all just a matter of calculations. It sort of is but the thing is we were just missing one. People who are weight reduced seem to burn 3-5% less (Leibel et al., 1995) at their lowered weight than we would expect so Laura actually has to eat 1250 calories a day if she is sedentary or 1700 if she is lightly active to maintain her new weight of 140 lbs. This effect seems to linger indefinitely as long as you stay below that initial starting weight (Fothergill et al., 2016). That means if Laura regains some but not all of her weight back she is still burning 300 – 500 calories less than she was before (Fothergill et al., 2016). In a classic experiment this reduction in resting metabolic rate only seems to go away when you get almost all the way back to that initial weight or are allowed to eat whatever you want (Keys et al., 1950).

Why this is the case is almost impossible to explain and pretty crappy for weight reduced individuals. Not only do you have to eat less than the average person at the weight because your resting metabolic rate is lower that never stops or readjusts but goes on for ever. If you gain some of the weight back it seems like there is no partial return to normal baseline levels. It also doesn’t seem to matter how fast of slowly you lose the wight in the first place you still seem to burn the same amount less per day. So at 140 pounds Laura has to eat 100 – 500 fewer calories less every day than her sister say she returns to 200 pounds she still burns 100 – 250 fewer calories a day than she did before losing the weight not 50! We don’t know why this is, what we can do about it other than consuming a bit less and there’s no biological reason that this should continue and follow the patterns it seems to.

What does this finding explain though?

Actually a whole heck of a lot! We know that most people who lose a lot of weight tend to regain a lot of it if not all, if not more than they lost in the first place. Re-gain seems to start as soon as dieters return to normal eating after their plan ends and they reach their goal weight. This newly discovered notion that someone who has lost weight ‘damages’ their metabolism starts to ring true doesn’t it? There is no direct evidence from these studies that your metabolism is ‘damaged’ in some way but it does ring true to the wives tale at least. It could also be explained by that old idea that your body has a set point that it ‘trys’ to get back to. Again there is no direct evidence of that here either but… 

What is does explain though is why the very moment you go off a diet you seem to start regaining the weight right away and fast. It explains why every diet seems to work for most but only as long as you stay on it and why it’s so dang hard to keep the weight off! It also explains some positive stuff you keep hearing too. We’re all sick to death of hearing ‘it’s a lifestyle change you have to make for the rest of your life!” Turns out that’s totally true.

Why this finding isn’t THAT big of a deal

It is a little bit of a big deal sure, but it might just be the biology behind all of the mantras we’ve been reading in women’s magazines for years. The other thing we knew about before this finding is the habits in common of people who do keep lots of weight off forever. The patterns that this finding explains were well known, well documented and well studied before we knew weight reduced individuals burn fewer calories a day. 

What this means that’s new

If you’ve lost weight and you want to keep it off you have to modify the calories burned calculations you might be looking up on line. That is you should multiply them by 0.95 to compensate for the fact that you’re now weight reduced. That’s all. If you start to regain weight consistently reduce your intake again using the same method.

How to keep the weight off then

People who lose a lot of weight and keep it off do exist and we have long known what makes them the successful ones in the bunch. There wasn’t much commonality in how people lost the weight but oodles in how they kept it off. If you want to be one of these kids, and why wouldn’t you, try to incorporate as many of these habits as possible. The other nice thing is these strategies are a great way to lose weight in the first place!

  • Exercise a lot. About an hour a day five days a week. Most people that keep a lot of weight off long term walk about this much. You don’t have to walk but it’s pretty easy and cheap.
  • Weigh yourself regularly and make small changes in response to the number. Maybe even daily
  • Track calories, plan meals and measure your food portions
  • Eat breakfast
  • Don’t allow yourself to make exercise excuses
  • Lift weights

(Hill et al, 2005 and Kruger et al., 2006)

This is a pretty cool new finding for sure and I think knowing about this weight reduced metabolic finding might make people feel fell better if they’ve tried and failed before. It might make people feel like this is the reason its so hard. But it is something relatively easy to overcome. Beyond that we already new the habits that were always going to up your odds of being successful long term. What do you think about this new long term weight loss piece of information. Does is give you an ah-ha moment?

Here are some other weight loss posts you might find helpful!

How to finally lose weight this year, no BS

The science behind weight loss plateaus

The myth of 1200 calories

What it means to live in an obesogenic environment

What is ketosis? Will it help you lose weight?

Read what I read

Fothergill et al., 2016. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity.

Keys, A., Brožek, J., Henschel, A., Mickelsen, O., & Taylor, H. L. (1950). The biology of human starvation. (2 Vols.). Oxford, England: Univ. of Minnesota Press.

Hill et al., 2005. The National Weight Control Registry: Is it Useful in Helping Deal with Our Obesity Epidemic? Journal of Nutrition Education and Behavior.

Kruger et all 2006, Dietary and physical activity behaviors among adults successful at weight loss maintenance. International Journal of Behavioral Nutrition and Physical Activity.

Leibel et al., 1995. Changes in Energy Expenditure Resulting from Altered Body Weight. The New England Journal of Medicine.

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