Does Rapid Weight Gain Mean You’ll Be Fat Forever?! | Health Guides Daily

Don’t get fat, because if you do, you’ll be fat forever! Fear! Woe! Despair!

This is how much of the media is interpreting a new obesity study out of Sweden. ‘Fat Forever’ certainly makes a good headline, but what they’re doing by spewing this hyperbole is violating the principle of Occam’s razor.

Occam’s razor is a principle that the simplest explanation to an event is usually the correct one. As an example, you do the laundry and a sock goes missing. Why?

1. An alien shape shifter that loves the taste of freshly-washed socks has taken the place of your dryer.
2. The mixture of tumbling and heat opens a wormhole into a parallel universe, but the hole is only large enough to allow socks to travel through.
3. You lost a sock somehow, somewhere. It might turn up, and it might not. Deal with it.

Occam’s razor asserts that number three is most likely correct. Go figure.

While those are extreme examples, the aforementioned weight loss study out of Sweden (PDF) has caused all sorts of complex assumptions to be made about losing weight where a simpler answer is quite likely more correct.

Published on August 25 in Nutrition and Metabolism, the study took 18 subjects of normal weight with a mean age of 26, and chunked them up with high-calorie fast food and sedentary living over a four-week period.

The result: You stop exercising and start inhaling lots of Swedish fast food at McBjornald’s House of Deep Fried Meatballs, and you get fat. Big surprise.

What surprised people, and had media around the world losing their collective poo in reporting on the study’s findings, was that these 18 participants had difficulty losing the weight afterwards.

Here are the basic numbers:

  • After four weeks, the glutton group gained an average of 6.4kg over baseline.
  • A year later, this group was, on average, 1.5kg over baseline. They had lost only 4.9 of the 6.4kg gain (again, on average).
  • Two-and-a-half years later this same group was still 1.5kg heavier than baseline on average, whereas the control group (those told to just maintain their current lifestyle) by comparison had not gained any weight over their baseline.

So, something about a lazy, month-long pig out makes it so you can’t lose all the weight afterwards? What is going on here? What are people who are reading this study interpreting as the culprit? Here are few of the theories:

  • You screwed your hormones all out of whack and now you’re doomed to be a hyper fat-storer for the rest of your days.
  • No, it’s not hormones, it’s metabolic rate that got screwed up. Because of four weeks of sedentary gluttony you’ve decreased your metabolism so that you no longer burn calories at the same rate you once did.
  • It’s all those chemicals and crap in the fast food. Lord knows what it did, but it messed up your physiology so that you’re now destined to be fat for all time.

It’s all fast food for thought, but I don’t think any of it is correct. Remember, Occam’s razor says the simplest solution is most likely the correct one.

So, what is the simple solution? I’ll tell you what I think:


Staying at the same weight is easier than losing it, because you only need to stay calorically balanced. To lose weight you need to sustain a caloric deficit until you reach your goal weight. Guess what? Deficits are harder.

To lose weight, especially to get down into a normal weight range, requires a significant and sustained effort. Getting back to the baseline for these 18 people wouldn’t be impossible, just HARD.

There are a few other things about this study to consider:

  • It’s one study.
  • There were only 18 people in the intervention group.
  • These 18 people were willing to be sedentary and pig out on fast food for four weeks as part of the study. This may say something about their psychology and motivation to lose all the weight afterwards. I don’t know how much they got paid, but it would take lots more than any research grant could afford to get me to take part in it.
  • We’re talking about 1.5kg here – barely over three pounds. I gain that over Christmas. Then I spend January busting my ass to lose it.

To reiterate, I don’t think gaining a bunch of weight in a short period of time up-regulates a bunch of fat genes or down-regulates slim genes or does anything else to metabolism or hormones on a permanent basis. I just think that a sustained caloric surplus causes weight gain, and that the months of caloric deficits it takes to lose this weight is very challenging.

So, if you’re slim, then don’t get fat. If you’re fat, then prepare yourself for some serious effort, because losing it isn’t easy.

James S. Fell is a Certified Strength and Conditioning Specialist and a middle-aged family man with a desk job and not much free time, yet he’s able to keep in shape because he loves exercise and doesn’t mind eating healthy. He is the author of Body for Wife: The Family Guy’s Guide to Getting in Shape.