weight loss?
March 2, 2010 1:14 PM   Subscribe

Weight loss question

I've been on a diet and have lost 15 pounds but recently seem to have hit a plateau. Talking about it to a friend I said that I may have reached the equilibrium between food in and activity out and the only way below the plateau was to eat even less or exercise more.

He thought this was wrong - that the diet/exercise which caused me to lose 15 pounds should cause me to continue to lose weight, since if it hadn't, I wouldn't have lost it in the first place.

My reply was that if he was right I could shrink to zero, which surely can't be right and that the idea of a plateau - x food in = y activity out was sound.

Who's right?
posted by A189Nut to Health & Fitness (15 answers total) 7 users marked this as a favorite
What are you eating? Food quality becomes very important as you slim down, moreso than simple calories in / out.
posted by outsider at 1:18 PM on March 2, 2010

You are right. Your body is a machine, and you may have adapted to your new caloric demands.

For weight loss, food quality does not matter. Food quality in and of itself may have other health benefits, but absolutely none for weight loss.
posted by unexpected at 1:19 PM on March 2, 2010

Your friend is closer to right than you are. If you weigh less, you're burning fewer calories than when you were at a higher weight, and you also need to eat fewer calories in order to maintain your weight. This is why the general calorie recommendation for men is higher than for women - because women are (on average) smaller.
posted by something something at 1:19 PM on March 2, 2010

IAMAD but I would defnitely say you're right. As you lose weight your body requires less food to sustain itself, and therefore to continue to lose weight you either have to reduce your food intake, or burn more calories (ie. push yourself harder at the gym).

Speaking as someone who has lost 80+ pounds in the past year and a half, whenever I hit a plateau I had to either change up my gym routine, increasing the duration or resistance, or change up my diet, eat different and new things and maybe eat a little less. Exercise, however, has always been the determining factor for me and is what makes the bigger difference.
posted by gwenlister at 1:23 PM on March 2, 2010

Take your weight, multiply it by 11--that is the amount of calories you need to consume per day to maintain your weight. (Not counting exercise.) So basically, what something something said.
posted by Melismata at 1:24 PM on March 2, 2010

This possibly relevant article was on the NY Times site today, about how your body adapts to your new caloric intake level.
posted by stopgap at 1:28 PM on March 2, 2010 [2 favorites]

You are absolutely right.

There was a funny little "paradox" I once heard about someone who has a stable weight (say 200 pounds) and is in the habit of eating a banana with breakfast every morning. The idea is that if the person stops eating the banana and keeps the rest of their behaviour the same, they will eventually starve to death. This can be shown by the fact that a banana has ~100 calories in it and a pound of body fat represents about 3500 calories. So, since the person had a stable body weight before, they will lose about a pound a month until, within ten or fifteen years, they die of malnutrition despite still eating three rather hefty meals per day.

Obviously this is absurd.

The key lies in the Basal Metabolic Rate.

Lets say that your weight used to be stable at 200 pounds. This means that, if you were taking in 2500 calories per day, you were also burning 2500 calories per day (through a combination of exercise and base metabolism).

Then you went on a diet. You cut your calorie intake to 2000 calories per day and kept your exercise level the same. You lost about a pound of body fat per week.

And then, at 185 pounds, you stopped losing weight. The reason is simply that, now that your body is lighter, it requires less energy to keep itself running. So by doing the same activities you were doing before, you now only burn 2000 calories per day.

So, you are correct. If you want to lose more weight, you either need to cut more calories or you need to increase your exercise so that you burn more. The other key thing that your friend likely doesn't understand is what would happen if you went off your diet now.

Your weight has plateaued because you are consuming the same number of calories you are burning. If you are happy to stay at 185 pounds, then all you need to do is stay on your diet forever. If you go back to eating 2500 calories per day, your body will naturally find its way back to the weight at which it burns that many calories.

A diet isn't something you go on or go off. It's a lifestyle you convert to.
posted by 256 at 1:29 PM on March 2, 2010 [9 favorites]

Here's a pretty easy way to prove your point.

Ask your friend to carry around a 15lb weight for a day and then tell you he's burning the same number of calories during the day with the weight as when he was not.

(obviously there are a lot of factors here, fitness, diet etc but this is a pretty easy way to picture why your caloric needs would change)
posted by bitdamaged at 1:34 PM on March 2, 2010

Listen to 256, but here's another bit of advice that I've learned during my time working on weight loss... your body will eventually get used to whatever you give it, and learn to live on that. Your body is in a sense trying to maintain status quo, even if you're overweight. So if you reduced your diet to 2000 calories a day, and stayed very consistently on that for a long time, eventually your body would learn that as its "base" and you will probably start to lose weight slower. You may need a shock to your system every once in a while in order to shake your body out of its new habits. This is one reason why a lot of people recommend giving yourself a "cheat day" when you're on a diet.

Another piece of advice that I've learned very recently: don't starve yourself or reduce your calories by a drastic amount thinking that you'll lose weight faster. Your body will freak out and go into survival mode and try to hold on to all the excess fat you have for dear life.

Slow and steady wins the race.
posted by joshrholloway at 1:58 PM on March 2, 2010 [1 favorite]

A819Nut doesn't mention his exercise levels. If you're exercising, even light exercise like regular walking (and I mean like walking fast for an hour, not walking to the refrigerator) there's a certain point where you don't seem to be losing weight because you're gaining muscle mass. And that is a good thing.
I will advise everyone on a severe diet to watch carefully. I worked hard to lose weight for a full year, I exercised and dieted for a year. I went from 245 to 190lbs, and despite eating a carefully calculated diet, I ended up with a severe vitamin deficiency ("slimmers paralysis") that caused paralysis in leg muscles, the doctors thought I had ALS. And then I got gallstones and had to have my gall bladder removed. I was never so unhealthy as when I tried to get healthy.
posted by charlie don't surf at 2:53 PM on March 2, 2010

The body is composed of 4 main things:

1) Bone
2) Tissue (Muscles, organs, etc.)
3) Water
4) Fat

When you remove or add any of those things to the body, you lose or add weight. It seems very obvious, but this is something that people lose sight of when on a standard scale.

A plateau could mean that the body is at stasis. It could also mean that the body has lost fat, but is retaining water (due to menstruation, increased salt intake, or a change in percentages of carbohydrate/protein/fat intake). It could mean that the body has lost fat, and lost water, but due to increased exercise, has resulted in muscle growth and increased lean weight. Which is to say that a plateau in overall body weight means very little.

Doubtlessly you're dieting and exercising to lose fat, and not bone, tissue or any substantial amount of water. Your diet could well be successful, but your scale won't tell you -- it's entirely possible with a change in diet and exercise to lose fat and stay exactly the same weight. As you know from watching bodybuilders, it's entirely possible to use diet and exercise to gain a substantial amount of muscle without gaining a substantial amount of fat, to the point where they weigh substantially more than they used to -- while looking substantially more lean.

As such, a typical scale is a rather poor measure of whether a diet is working. If your scale's one of those fancy new digital ones that can tell you your percentage of body fat, that can be useful during a diet to ensure that you continue to lose fat. But a scale that just tells you your weight? There's little reason to get on one while you're dieting.

So, let's assume that you've gotten one of those fancy body fat percentage scale, and indeed, over a substantial period of time, you're no longer losing body fat on your diet. This could mean four three things:

1) You've maintained a consistent amount of lower-than-typical caloric intake, but you've actually become less active when outside of your exercise routing, resulting in less physical activity.
2) You've maintained increased activity through exercise, but have actually subtly increased your caloric intake to a point where it compensates. This is amazingly easy to do if you were engaging in a small caloric deficit by subtly changing portion sizes, or started eating items with slightly higher caloric content.
3) Your calorie and activity level actually didn't change all that much with the new routine, but the changes in the way you were eating and moving resulted in a substantial amount of water loss.

In the case where your body weight has plateau'd but your body fat is decreasing, your friend is right, and you should just keep waiting, and you'll likely encounter the positive aspects of your diet shortly, on your waistline if not on your scale. In the case where both your body weight and body fat is stable, you'd be right -- you would need to further drop caloric intake and/or increase activity in order to continue to lose weight.

So, what about the whole shrinking to zero thing? Any time people talk about this, folks always bring up this ridiculous urban method about losing weight, that there's some kind of "starvation mode" where the body will stop losing weight if you eat too little and try to hold onto fat.

Complete BS. There's a good write-up on why the notion of a starvation mode is silly and based on an incorrect analysis of a limited study. But let's look at two quick facts:

1) Anorexics cut their caloric intake drastically while maintaining moderate to high levels of activity. In spite of greatly diminished caloric intake, they don't encounter a "starvation mode," and do continue to shrink inexorably. While they don't technically shrink to nothing, they do shrink to the point where their body no longer has fat or muscle tissue to burn, and they die of cardiac arrest as the body no longer has energy or nutrients to continue to function.

2) Individuals who have weight loss surgery, and are physically able to only eat enough calories to support a lean (or at least leaner) body, continue to lose a very substantial amount of weight for many years until they reach equilibrium between caloric intake, body composition and activity levels.

So your friend is right. You can set a limited caloric intake, keep a regular regimen of exercise, and you can just keep losing. If you set that limited caloric intake too low, you'll end up shrinking to the point where you'll die.

In reality, what happens to most people is what I mentioned above: they start eating more or they start exercising less.

Both of which, in our society, are really easy to do.

Bonus bad diet advice de-bunking: you know that thing about multiplying your weight times 11 to get something approximating your metabolic rate? It doesn't work. A pound of fat requires substantially fewer calories to maintain than a pound of muscle. A 250-pound male bodybuilder of moderate height might well need to eat 4000-5000 calories a day to maintain their weight, while a short, inactive, 250-pound man with little muscle mass may only need 1800 calories a day.

(So, if a dieter makes sure they have the right nutrients (primarily protein) to maintain their tissue, and exercise to keep their tissue in good shape while dieting, it actually is possible to lose fat without having a significant change in your metabolic rate. If you don't get enough protein and nutrients, or don't exercise and let your muscles diminish, you will end up "lowering" your metabolism.)

As such, the fact is that it's pretty tough to tell how many calories your body needs without holding your caloric intake and activity level steady in a controlled fashion and finding out how much you lose or gain, and then make small adjustments from there. You're better off selecting a rather low but healthy amount for caloric intake -- where you're certain it's much less than you need, but not so low that you'll be missing vital nutrients to maintain muscle tissue -- so that you don't inadvertently set a target number of calories that's actually *greater* than your metabolism needs, and end up plateauing or gaining weight.
posted by eschatfische at 3:37 PM on March 2, 2010 [5 favorites]

I should really do a better job of proofreading my posts:

one of those fancy body fat percentage scales

This could mean four three things:

ridiculous urban method legend

well will need to eat 4000-5000 calories a day
posted by eschatfische at 3:47 PM on March 2, 2010

Read the book Good Calories, Bad Calories by Gary Taubes. A lot of the answers presented here are flat-out wrong, and the short of it is that "a calorie is a calorie is a calorie" isn't really supported by the relevant studies no matter how much people repeat it as if it were gospel. Eating fewer calories and exercising more will only take you so far, and you could actually eat more calories and exercise less and lose more weight if you change what you're eating. What you eat does matter, and the book gets way deeper into the science and the reasons for why the current misconceptions exist than I or anyone else has time to do in an Ask MeFi answer. The short of it is that it mostly has to deal with the hormone insulin and what it actually does in your body. The book isn't a diet book, but a comprehensive evaluation of roughly a hundred years of major dietary studies and more. Spoiler: avoid refined carbohydrates.

I had years of my own personal experience before the book even came out so that made it a lot easier for me to accept its conclusions. Absolutely serious, here: I could not lose weight eating 2000 calories a day, 1500 calories a day, 1200 calories a day, got desperate enough to try 100 calories a day, all this even with a lot of exercise, during high school. I'm female and I was roughly 40 pounds overweight. I ate, literally, no shitting, 5000 calories a day several times a week on low-carb with about 3000 calories the other days with next to no exercise and I'd lose three pounds a week and all my blood work would be much better. I did low-carb for about four years, generally eating a lot and just got thinner, then I stopped during college largely because not having access to a kitchen was too prohibitive for me -- I need lots of variety in my food or I go nuts. Bam, I gradually gain almost 70 pounds over the next four years, and I wasn't eating a ton or anything. I tried low calorie diets again and actually kept gaining weight. I gave up for a while aside from a little exercise which never did anything. Last December I got sick of it, started up low-carb again, bam, thirty pounds down in three months and I'm eating roughly 3,000 - 4,000 calories some days and not doing shit for exercise until just the other day, since I actually enjoy it again. Blood work is beautiful.

Saw the same thing happen to my parents and aunt. My dad didn't have to take several of his medications when he would stick to low-carb, too.

People can say all that isn't possible until they're blue in the face or that it's unhealthy for whatever reason but frankly, I'm not interested in arguing with anyone over something I've tracked compulsively and experienced for years. Taubes's book explains it all.
posted by Nattie at 4:39 PM on March 2, 2010 [7 favorites]

It's math.

An average woman need 10 calories per pound to maintain her weight.* A 200 pound woman needs 2000 calories, 150 pound woman only 1500 calories. When you lose weight you need fewer calories. You need to drop your calories or increase your activity to continue to have a gap between consumption and burn.

In short, that it worked before doesn't mean it'll work now.

*10 calories per pound is an estimate. Medline NIH has it slightly higher, but I've recently read some research that argued for a lower number since American's are increasingly sedentary. Whatever your exact calories per pound, it's important to note that as you lose weight it gets more difficult to create a calorie deficit.
posted by 26.2 at 5:32 PM on March 2, 2010

I don't think it's possible to accurately answer your question without more information from you.

You might have plateaued -- not because of your calory intake and requirements, but solely in terms of exercise. If you did 45 minutes on a Stairmaster every day, with no variation in time or intensity or rhythm, eventually you would stop losing wait, but it would not be impossible to resume losing weight, by varying the workout.

It's also true that when you are burning roughly the number of calories you're consuming, to put it simply, you would roughly maintain your weight. But not all instances where someone ceases losing weight are going to be instances of this.
posted by troywestfield at 9:16 AM on March 3, 2010

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