If, for example, you always manage to stay within a healthy BMI is gaining and losing 15-20lbs continuously really worse than being overweight? If your diet is always on the healthy side, just varying in calorie intake? I always hear how yo-yo dieting is so bad for you, but isn’t this what many athletes do when they get ready for competition?
I’ll give this one more chance as I really would like to know.
I’ll admit that I yo-yo constantly. It just works for me. The world seems to tell me this is a failure on my part, that I am unhealthier than a stable weighted obese person. Maybe they are right, but I’d like a little more certainty as most of the articles I’ve seen decrying it seemed to focus on people yo-yoing between healthy weight and obesity.
From what I can find in a cursory search, there is no concrete data that suggests weight cycling is harmful. I can find a few studies that suggest it may cause people to gain back more fat in the weight increase part of the cycle, and may possibly lead to deterioration of vital organs and osteoporosis (due to restriction of calories and nutrients), but on the other hand, there are a number of studies that also show no effects (on rats, mostly).
I would suppose the biggest risk would be on mental health.
I should add that weight cycling, imho, generally means the person really isn’t making the right changes in their lifestyle to maintain a healthy weight for life. If a person loses 20 pounds in a couple of months, it’s likely due to calorie restriction (barring a medical reason). What people then do is go back to eating as they did before and regain. While this probably isn’t THAT harmful to their health, they aren’t really addressing their issues with food, are they? It’s a draining cycle, and doing it over and over is frustrating.
What people need to do is stop dieting and start eating properly. No fast food, no processed food, a diet full of veggies, fruit and protein. Unfortunately, a lot of people can’t seem to live without crap food though.
Renton_lvr, why is your weight going up and down? Does it go up and down without your even trying? Or are you constantly going on a diet and then giving up a couple of months later? If it’s the latter, you should pick a level of eating (in quantity and quality) and exercise that you can stick with over the long haul.
You are misunderstanding what athletes do. Firstly, they are NOT fluctuating between being overweight with a surplus of fat stores and then dropping it. When you hear something like “Look at Rocky! He’s gained 20 lbs for this boxing match!” they are talking about a workout regimen that has added 20lbs of muscle. That muscle weight may gradually decline again if it’s too hard to maintain.
Yo-yo dieting stresses your metabolic system. Athletes do NOT crash diet. Food is fuel. They will not be able to perform if they restrict their diets. The weight dropping part of a yo-yo diet tends to be very restrictive and the lack of food diversity can result in serious nutritional deficiencies. Mess with your potassium and sodium levels too much and the resulting electrolyte imbalance can mess up the regulation of your heartbeat - something no athlete would want to do.
Just to clarify, I am not speaking of “crash-dieting” where one consumes under 1200 calories a day. I am speaking of the weight loss stage as being in the 1500 cals. per day (for a woman, by the way) range. I would imagine the weight gain cycle would be closer to 2500 per day avg.
So let’s forget the athlete, I remember reading an interview with an actress who spoke of her ‘movie’ weight (that pesky weight adding camera) being 10 lbs lighter than her everyday weight. Is that unhealthy to be changing constantly like that if it’s always in a healthy range?
It isn’t bad for you, unless you’re extreme about it and are throwing off your electrolyte balances for instance.
As for metabolism, yes it effects you but not so much you’d notice. Even after years of yo-yo dieting the difference between a non-yo-yo dieter and a yo-yo dieter would be about 100 calories a week. Which amounts to less than half a candy bar.
It wouldn’t make enough difference to actually see any physical difference.
Bodybuilders, especially non-steriod users, will use crash diets as a way to gain a bit more muscle.
For example, a person can only add between 10 - 15 pounds of muscle per year. Anything else is fat. If you use steriods you can add more. If you eat at random you will also gain more muscle but it will be mixed with fat. In most cases the extra fat will negate any extra muscle and make you look worse.
But then again, some people can carry fat well. For intance, having the classic “bubble butt” is mostly fat, but it’s fat stored in a place people find acceptable. In other words when fat sticks out of your ass it’s good, but when it sticks out of your gut you’re a fat slob 
Anyway, if you don’t use steriods and want to gain more than 10 or 15 pounds of muscle, you can eat more. And then you can diet quickly to zap off the fat.
Does this work? Yes, to a minor degree. This technique will allow you to gain 2 or 3 pounds of extra muscle per year.
This works for bodybuilders but not for your “average joe.” Why? Because 2 or 3 pounds of extra muscle isn’t going to make an average joe any more noticable. It’s not enough.
But on a bodybuilder the difference between even half a pound of pure muscle can mean the difference between a first and second place finish. A first place winner can win thousans of dollars in a contest, while the second place winner get’s squat.
I was involved back awhile around 2004 in a study at the University of Chicago with metabolism and sports med and basically it’s very difficult to alter your metabolism. You certainly don’t do it by “eating a sandwhich” and throwing it off.
Unless you have a true metobolic disease like type 1 diabetes or thyroid (over or under) stimulation any metobolic changes your body makes are on such low levels, that you don’t see them unless you measure with precise scientific intrstruments.
Although I know people who claim they can tell one someone has lost a pound, I find it unlikely you could tell the difference between a man who weighed 150 pounds this week and now weighs 149.
As I said, the metobolism does go down. There’s no doubt about that, and that is what books about these diets exploit. It IS true, you can’t debate that. But the amounts of change are so small you won’t notice anything.
Of course then the book (usually at the end) blames you for “not really following their plan”
Does it hurt you? Like I said, if you’re extreme about it, it can. Electrolytes can be thrown off if your aggressive enough. While this may not be a problem in a healthy person, if they are thrown off once in awhile, if you have a hidden condition, it may make issues for you.
For example, we now know, Karen Carpenter most likely died because she was taking large amount of thyroid pills to stimulte her thyroid to speed up her metabolism. That coupled with the extreme dieting and electrolytes threw her heart rhythms way off.
I think a lot depends on other factors, like the muscle/fat ratio, how fast you’re cycling weight, how extreme the variance is, your overall health, and probably other things I can’t think of at the moment.
It is somewhat normal for a person’s weight to fluctuate anyhow - for women, in particular, a 5-10 pound weight variance over the course of a month might have more to do with hormones than anything else, and what you’re describing isn’t much more than that.
Markxxx, can you please cite, specifically:
Not being rude, just interested.