Do Synthetic Fat Substitutes Make You Fat? Ask the Rats Who Ate Pringles

Photo: jetalone

In a whopper of counterintuitive research, and another reason to look askance at that supposed wonder of modern food science olestra (Olean), a study published by the American Psychological Association shows that synthetic fat substitutes used in low-calorie potato chips can backfire and contribute to weight gain more so than their fatty counterparts. How do we know? Researchers at Purdue fed Pringles to lab rats. Yes, the mathematically perfect, Einstein-inspired Pringles. Here’s how it worked:

The rats were split into two groups. One was given a high-fat diet, the other a low-fat diet. Half of each group was then fed Pringles, while the other half was fed a combination of Pringles and Pringles Light, which are made with olestra. For rats on the high-fat diet, the group that ate both types of potato chips consumed more food, gained more weight and developed more fatty tissue than the rats that ate only the regular Pringles. What’s more, even after the Pringles were taken away, the fat rats stayed fat. As for the rats on the low-calorie diet, they didn’t experience weight gain from either of the Pringles. But, when they were switched to a high-fat diet, the rats that had eaten both types again ate more food and gained more weight and body fat than the rats that had eaten only the regular Pringles.

The conclusion is that olestra tricks the body with its empty promise of high calories. Foods that taste fatty trigger all kinds of things in your body, including metabolic reactions, in anticipation of a big burst of calories. (Remember Seth Roberts‘s “Shangri-La Diet“?) When the calories don’t come, things get screwy. Considering all the other well-documented side effects that olestra can cause, this doesn’t bode well for a product that’s already had trouble catching on — although, according to a Procter & Gamble website, we’ve already eaten more than 6.6 billion servings of the synthetic fat.

(HT: Eric M. Jones)


"When the calories don’t come, things get screwy"

Could you expand on this?


i like the conspiracy theory is that food preservatives build up in you and preserve your fat. like how french people eat lots of full cream, butter, high saturated fat foods and and aren't all fat. Their food is all natural and fresh. while people over here in america, eat healthy, low fat and diet foods that are processed and have preservatives/additives in them and people have lots of trouble loosing weight.

anyone else have a take on this theory?

Joshua Northey

My take is people in France burn more calories. Particularly they walk a lot more, drive less, and sit at desks less. That is at least as important as food differences, but I am just guessing based on the time I have spent there.

I bike between 10 and 30 miles for a commute/meetings/errands everyday, rain/snow or shine, in the US it is still fairly notable and rare, in France it is much less odd.


There has been so much debunking on the calories in, calories out myth now that I'm shocked that people still don't get it. Yes it's true that thermodynamics contains laws that we must all abide by, but we don't have complete control over calories in or out. For the sake of argument, lets say that we have complete control over the calories in, i.e., you control exactly what you eat and you know exactly how many calories you're getting. So that's at least constant (or known). Now what you don't control is calories out. You may think you can control that by exercising more or taking the stairs instead of the elevator. But you have much less control over your calorie expenditure than you think. Your body is no where near 100% efficient. That is, to do 1 calorie of work (1 food calorie is equal to 3000 ft-lbs of work - that means lifting 3000 lbs 1 ft, or 1 pound 3000 ft, or any product in between) it takes more than 1 calorie of energy. So if you weigh 150 lbs and walk up 20 ft (2 stories) of stairs, that's about 1 food calorie of work done. But since you're body is ON AVERAGE 12% efficient, you really burnt about 8 calories to do 1 calorie of work. The trick is that the efficiency is really determined by WHAT you eat, now how much you eat. If you eat a low carb, high fat diet. Your body will adjust to be LESS efficient, meaning you burn more and store less. If you eat a high carb, low fat diet your body adjusts to be MORE efficient where you burn less and store more. So you can be all Biggest Loser and work out for hours a day and it doesn't matter (notice how often they're surprised that they didn't lose weight even though they "got their burn in"?). So what does this have to do with the above story? Eating the fake fats can trick your body into adjusting it's efficiency, so even though the fat itself has 0 (or near 0) calories. Your body is going to store energy from something else you ate. I've ranted enough here for a comment, but I really wish I could convince people that how much you eat (within a pretty wide range of reason) doesn't matter, what matters the most is WHAT you eat. Though if Gary Taubes couldn't do it in his treatise, then maybe we're all just doomed to repeat the same "common knowledge" over and over until we all die from obesity related complications.



And yet, I've lost 44 pounds this year eating mediocre food (often fast food lunches) simply by counting (and restricting) my caloric intake.

I'll give you that good food can only help, but the calories-in calories-out "myth" hasn't been debunked.

One problem is that people think exercise burns significant amounts of calories. It doesn't. You want a honey bun? Great, go jog for an hour or so. Not walk around the office once.

You can effectively count caloric intake, and you can reasonably guess your daily expenditure. Unless you are obese. Obese people tend to grossly underestimate what they are eating, and grossly overestimate their calories expenditure. Then they reject calorie control as a weight loss method that works for them.

For example, I submit Extreme Home Makeover's Weight Loss Edition. They had a girl on there a few weeks back who exercised 4-5 hours a day. But she didn't control her calories. She lost 3 lbs in 3 months. When she lost 90 lbs in a previous 3 month segment, she was controlling her diet.

Taking the stairs does not increase your calories out. That's the myth in your post. If you think that taking the stairs is going to shave off even a pound, I hope you work on the 50th floor.



Here we go again, why is your "success" more valid than the "failure" of CI/CO to reverse obesity to the extent that it shows up in a statistically significant way?

Seriously, what does "Then they reject calorie control as a weight loss method that works for them. " mean? People reject things that don't work? Call the police, don't you?

And no, evidence does not show that fat people "grossly underestimate their calorie intake", it shows that the more pressure people put on themselves (and/or is put on them) to reduce calorie intake dramatically, this is likely to alter the way intake is remember. Its the brain's desperate attempt to fulfil a demand it wasn't designed for.

It's a bit like straining for a crossword puzzle clue and at some point your brain starts churning up words to try and meet your demand for what it either doesn't have or can't locate.

When there is no pressure to lower calories or to be thinner, fat people can estimate their calorie intake as well as anyone else.

And sorry, unless you are well into the underweight category 44 pounds means you probably started as 'obese' yourself, so according to you, couldn't possibly know how much you were eating and exercising, thereby challenging your own explanation for your weight loss.



We're not far away from turning off or turning down the gene that makes our fat-storage so efficient. They can already do this in mice. At this point the developed world's residents do not need that survival utility that causes us to "hang on" to all those extra calories in case the next harvest is meager. Our collective lifestyle has far outpaced our evolution. Perhaps though we could never evolve to tell our genes to just chill out, for the next nutrient-rich meal is just a few hours away.

There are many reasons why Americans have obesity problems, and keep in mind it's far more prevalent in the deep south, moderately problematic in the midwest and northeast, and far less severe in the mountain west and Pacific coast, and it also correlates with lower income.

- great marketing (larger portions, 500 calorie bagels, fast food chains)
- beverage calories (alcohol, pop aka soda, lattes, etc)
- environmental chemicals that promote obesity
- cities built around the automobile



I don't think it will be that simple any time soon to just "turn off" the fat storage gene. Even if it is turned off, obesity is a problem that isn't going away any time soon. Also, although it is true that being overweight is correlated with income, this does not mean that there isn't a huge number of people making quite decent incomes who are also more than just a little overweight. Many people of these people have a lifestyle where they are working too many hours and getting little or no time to dedicate to their health. I think this is all too common in the United States. Also, just because obesity is much more prevalent in the South doesn't mean that it should be minimised as a "non-severe" problem. Keep in mind that the state that currently boasts the lowest obesity rates (Colorado) would have had the highest obesity rate 20 some years ago at that figure.

Eric M. Jones.

If I remember my non-Euclidean geometry, saddle shaped geometry (hyperbolic paraboloids) is the work of Riemann and Lobachevsky. I don't think Einstein had anything to do with it.


I have always had a similar experience with beer. One glass of a heavy tasting porter can have fewer calories than several glasses of the watery beers which may ultimately have more calories. You consume more of the latter as they are "less filling."


Artificial Sweeteners apparently have a similar affect, (Scientific American Article: ), distorting the brains understanding of how sweetness relates to caloric intake causing people to consume more sweet foods.


This study is incredibly suspect. It appears that they tried to set up some controls, to make a comparison between synthetic and natural fats, but there are too many other confounding variables: Carbs is one of them.


I'm confused. At the beginning of the article, you say that the only two experimental groups were high-fat and low-fat diets. Then towards the end of the second paragraph, you say "As for the rats on the low-calorie diet...." Which rats on the low-calorie diet? Did I miss something?