Why We Get Fat ~ Fast Food?

I'm on the record with my belief that a goodly portion of those struggling with excess weight got that way by "passive overeating".  It's certainly how I got my fattest in my post-ED years.  

So I came across this study:  

Background: Fast-food consumption has increased greatly in the USA during the past three decades. However, the effect of fast food on risk of obesity and type 2 diabetes has received little attention. We aimed to investigate the association between reported fast-food habits and changes in bodyweight and insulin resistance over a 15-year period in the USA.
Methods:  Participants for the CARDIA study included 3031 young (age 18–30 years in 1985–86) black and white adults who were followed up with repeated dietary assessment. We used multiple linear regression models to investigate the association of frequency of fast-food restaurant visits (fast-food frequency) at baseline and follow-up with 15-year changes in bodyweight and the homoeostasis model (HOMA) for insulin resistance.
  • Fast-food frequency was lowest for white women (about 1·3 times per week) compared with the other ethnic-sex groups (about twice a week). 
  • After adjustment for lifestyle factors, baseline fast-food frequency was directly associated with changes in bodyweight in both black (p=0·0050) and white people (p=0·0013). 
  • Change in fast-food frequency over 15 years was directly associated with changes in bodyweight in white individuals (p<0·0001), with a weaker association recorded in black people (p=0·1004). 
  • Changes were also directly associated with insulin resistance in both ethnic groups (p=0·0015 in black people, p<0·0001 in white people). 
  • By comparison with the average 15-year weight gain in participants with infrequent (less than once a week) fast-food restaurant use at baseline and follow-up (n=203), those with frequent (more than twice a week) visits to fast-food restaurants at baseline and follow-up (n=87) gained an extra 4·5 kg of bodyweight (p=0·0054) and had a two-fold greater increase in insulin resistance (p=0·0083). 
Interpretation:  Fast-food consumption has strong positive associations with weight gain and insulin resistance, suggesting that fast food increases the risk of obesity and type 2 diabetes.
Presented without further analysis :-)


Helen said…
Astounding! I wonder if this theory will gain any traction....
Stephan Guyenet said…
That is an awesome study. The difference in fat gain across tertiles is huge. I think fast food is the human equivalent of the rat "cafeteria diet".

I also think fast food consumption is partially a marker of other processed food intake (and there will inevitably be some other residual lifestyle confounds as well). These people are feeding themselves on foods that are professionally engineered for maximum reward value.
OnePointFive said…
I'm quite surprised to learn that'effect of fast food on risk of obesity and type 2 diabetes has received little attention.' after all everyone talks about it.
It always seems that obesity has followed the spread of fast foods from the US into other parts of the world and sadly it seems we can't stop it's spread.
In my part of the world, very rural France, local farmers (and outside activists) dismantled a newly built McD. and dumped the remains in front of the town hall. Not so many years later the same town has 2 McDs.
France doesn't yet have the same numbers of overweight and obese people but childhood obesity is increasing fast.
I like the theory suggested by Richard Wrangham. (Catching Fire,how cooking madeus human ). Highly processed foods; and fast foods tend to be higly processed are softer, and digested far more efficiently than less processed foods.
There was a trial on food texture, where rats fed soft foods became fatter than those fed hard foods http://jdr.sagepub.com/content/82/6/491.full
Anonymous said…
Where's the part about 'passive overeating' in this study?

I read it. I used to think fast food was the scourge of modern civilization, but now I just think it's fast. Fast food is fast... food.

Should it be food that fits someone else's idea of healthy? It's fast food, meant to be eaten on the run, or if you can't afford better. Or just because it tastes good. That works for me. Sometimes I am running somewhere, sometimes I can't afford better and sometimes it just would taste really good at the moment! Doesn't mean I have to overeat it (or overfeed, as they say).

(Coincidentally, I found myself waiting in a train station tonight, one that had a McDonald's for commuters. I already read the study, this morning. I looked at the menu and remembered every niggling criticism of the food I've ever read - the oatmeal's not right, the yogurt's not right, the burger -no matter how small- is not right, the salad's not right. All I could think was: oh, shut up.)

That was the non-passive me. I ordered a black coffee. It was delicious.
Harry said…
@ eulerandothers

Of course you're right...there's nothing inherently fattening about food that's not prepared versus food that takes time to prepare.

But, the vast bulk of fast food is also highly-palatable food (loaded with engineered ratios of sugar, fat and salt) that encourages over-consumption and reward-seeking consumption (as opposed to eating to satisfy hunger).

The business model for a fast food business that sold boiled rice, boiled potatoes, grilled chicken, garden salads etc. (sans the fatty, salty and sugary dressings that is) would be very problematic...the industry is built on getting time-poor customers to walk past the door of other establishments and into your doors...experience has shown that the best way to do this is to make the food super rewarding.

Anonymous said…
@ Harry,

How right you are. That stuff IS engineered to 'encourage overconsumption.' It smells so great, it combines all these great flavors, etc. What a nerve those people have, doing such a thing! I don't want to shame them for that - I'd like to congratulate them because I know how to make this stuff myself and it's a royal pain in the butt.

There is a series of recipe books that gives you all the recipes for that yummy fast food. I bought those books and set to work, making myself a McDonald's fillet of fish sandwich. It can be done. It takes longer, of course, and it's messy in MY kitchen, and if I'm going to go through all that, I'm going to make five of those things, not just one.

I can buy just one fillet of fish sandwich at McDonald's and be done with it. In the past 15 years, that sandwich has actually shrunk in size and has fewer calories and less fat.

Would I rather have a really healthy fast food business in the train station that sold boiled potatoes and grilled chicken and garden salad? Sure, let someone competitive business person have a go at that. It better be cheap! Because it has to be competitive, no?
Sanjeev said…
> It better be cheap! Because it has
> to be competitive, no?

Usually it means cheaper, but not always.

The corporate-suit-dilbert's-boss-fad[0] in Canada for a couple of years was to make outrageously huge-calorie, hugely beefed, cheesed and bacon-ed products (available via drive-through, natch) with a higher profit margin.

That's been in decline for a while, so I guess the joy (and profit margin) went out of figuratively saying

"in your face, gubmint !!"


"in your face, vegetarians, rice cake grazers and granola munchers !!"

Like the Seinfeld episode where Jerry's date looked at him suspiciously for ordering salad instead of a half-cow-sized steak.

Those were some of the major marketing messages from local radio & TV as I remember them.

[0] dressed in common-man drag, of course
Sometimes I sit around and think "I'd sure like to eat some food engineered to encourage overconsumption..."

Seriously, it is palatable but not that addictive. It would be more helpful to think of it like this.

A person eats a diet high in sugar and fat.

A person becomes overweight and insulin resistant.

A person becomes more prone to low blood sugar.

A person does not have food ready when they get hungry.

A person then has to make an urgent decision about eating.

A person opts for the path of least resistance...and gets fast food.

A person buys their preferred food high in fat and sugar...and the circle is complete.

Market testing is far more important for selling fat and sugar than supposed engineers of overconsumptionology.
Anonymous said…
@ charles,

It's actually not more helpful for me to see that list of steps. There is too much individual choice involved in eating for me to feel there's any 'circle' involved there!
CarbSane said…
@Charles: I've always had trouble with the notion that becoming overweight and insulin resistant would lead to hypOglycemia. Not all IR become hypERglycemic, but that seems to be the direction of glucose control. And as a person becomes more IR, the tendency would be for BG to stay elevated/come down slower after a meal.

By some "magic" processed foods tend to desensitize us to sweet and salt. When I used to eat a lot of take out or convenience foods, I added a LOT of salt to my own dishes when I bothered. As I now eat practically no take out/convenience food, I notice the saltiness/sweetness.

For example I ate a mini Reeses leftover from halloween and I couldn't finish it! A mini! I used to have no problem eating a regular 2 pack. Yesterday at Costco I tried a sample of some fiber bar. Just that little bite was so icky sweet. Most savory prepped foods are too salty for me now, and I love salt!

I just can't get over the calorie counts on dishes at places like Chilis, Applebees, TGIF, Olive Garden, etc.etc. Entrees are rarely under 500 cal and most top 1000 cal. That's just the entree. Somehow if I make the same thing at home it doesn't have half the fat and calories b/c it would be greasy. Industrial foods seem to taste better with higher fat so they put emulsifiers and stabilizers to keep them from getting greasy. Stuff like that seems to be at play here.
CarbSane said…
@euler: There was no mention of "passive overeating" in the study but fast food consumption leads to PO in my opinion. There's also something about the portioning rather than eating "family style" at home. If you're on the go the "doggy bag" is not an option and my generation was raised not to waste (starving kids in Ethiopia and all that). So you get a deal and finish it.

Think about something as simple as canned soup or chili or stew. Most cans are 2 servings, but half a can is not enough. How many people will just eat like 3/4 of the can and save the rest for later? Whereas yesterday I made a big ol pot of beef stew and serve myself what I want. There's enough to feed us for days so there's no compulsion to have to finish anything. I want leftovers!

My stew has less fat and no sugar than anything commercial. Not because I make it low fat by any stretch (I use chuck). Couple the lower calorie punch with the portion thing, and it's easy to see how eating fast foods => passive overeating.

Many fat people are that way because they are lazy. I was. Lazy about food choices! Once you get in a groove with preparing food at home, though, in this modern world, it's super easy, just as convenient and cheaper. I freeze sauces & stews & such. I can thaw that in the microwave in a few minutes - fast food!

I would like to thank the food researchers, however, for steamable microwave veggies. :)
CarbSane and eulerandothers,

If one is IR then one has insulin levels that are too high. If I wait too long to eat or I do something stressful or physical or otherwise demanding of glucose then I find this raises my insulin sensitivity temporarily...then CRASH!

It reminds me of my first dog. He was very sweet to me, but if I put my hand near his food dish while he was eating...WATCH OUT! I totally get that now.

In that state of mind I just want stress-free food. Chips from the cupboard, something to microwave, fast food, something easy and unlikely to lead to frustration.

I am not suggesting fast food is the only choice people will make. I am suggesting that when an overweight person is caught without prepared food handy, they are FAR more likely to go get fast food than to patiently shop at the grocery store and then go home to leisurely prepare a healthy meal. Of course there are other factors involved (such as how close the nearest fast food place is, personal economic restrictions, etc.)

Perhaps it doesn't happen like that for others. Maybe my situation is unique.
Tonus said…
And like many businesses, the fast food model is based around selling you as many additional items as possible. You may have walked into the door intending to have a burger, but you walked out with a double-cheeseburger, fries, a soda, and possibly a dessert of some sort.

The conventional wisdom is to blame the fat in the burger patties, but in the scenario I just described, those burgers come along with a convoy of sugars and starchy carbs. It'd be interesting if we could ever know what was being ordered by the people who gained the least vs the most weight.
Anonymous said…
I rarely eat a hamburger at anyone's home (barbecue, picnic, casual dinner, etc.) that even comes close to being as small as a McDonald's hamburger. McD's offers a hamburger - 1 hamburger - which is quite small. The rest of the choices are large, it's true. But that hamburger, and the single cheeseburger, or a Happy Meal with small fries - are all much smaller than what I would make or eat at home. Or anyone else's home, for that matter, if they are entertaining.

My opinion is that fast food doesn't lead to passive overeating. Not paying attention to portion size and the effect of that on calories does. Which can happen wherever you eat.

I only discovered by chance that McD's fish sandwich has fewer calories - the nutrition information is written on the side of the box - who knew?

Mindless eating creeps up, it's true: I've gained weight when I didn't pay attention to how many calories I was putting in my mouth. That takes effort and mindfulness. I count calories and get swept up in a day's activities, often forgetting that I ate something. Right now, I'm reminding myself to count 4 pieces of toast with peanut butter that I ate at 2 a.m...

The idea of eating just to satisfy hunger is something I WISH I could do. But, in fact, I eat to enjoy tastes. Unlike carbsane's sensitivity (and loss of sensitivity) to salty tastes, I have a sensitivity to sweet taste. No amount of fast food has deadened that - I really don't enjoy food that tastes sweet. I like fruit now because most fruits actually taste less sweet, diluted somehow by their water content.

My own cooking, off-diet, is much more caloric than anything I would have in a restaurant. I can't even eat my husband's cooking - it is so delicious, so I have a 'sample' of what he has made for dinner. It's sausage, peppers and onions, for example, fried in oil. Or chicken marsala, spaghetti and meatballs, etc.

I'm glad to get out of McD's with one fish fillet sandwich!
CarbSane said…
@euler: I'd have to say you seem to be the exception to the rule on this one. Yes, the 5-ish ounce "Alton burgers" we make at home are quite a bit bigger than a burger at McD's, but when I find myself getting fast food, I'm at least getting 1/4 lb and it's going to have some cheese and/or bacon on it. Fast food burgers are not that palatable to me. The smoke stacks smell delish, but the food isn't even all that tasty in the end.

I'm extending "fast food" to those family restaurants - they are always packed in my area. There are no puny burgers in these places.
CarbSane said…
@Helen, Stephan & Onepointfive: I think that the CAF rat study really shows one thing so clearly: it's not fat ... it's not carbs (even sugar - and I find that surprising) ... it's the combination in a certain form.

After all, I've known lots of folks who were successful on Zone and other moderate plans. But fast foods joints manage to concentrate calories. I'm not even sure they are that ultimately palatable - but "engineered palatable" which I think is a bit different. Really, I don't find fast food all that tasty, but just tasty enough to make you want more. Don't know if that makes sense.

Stephan, I definitely agree that "fast food" is correlated with manufactured food in general. When I got obese I wasn't eating a lot of what one would consider fast food, but I was eating mostly take out and pre-packaged convenience foods.

Even the Near East rice is an abomination compared to just making some good rice and adding a bit of spice, salt and butter!
Anonymous said…
@ carbsane,

I am the exception to the rule - I'm counting calories. If I can 'afford' the calories of a Big Mac, I'd have one, but, unfortunately, that flavor is just a memory for me at this point.

Plus, I actually love the taste of the single, puny McD's hamburger. There's a '5 guys' near my house that would put any lumberjack under the table with their burgers. But 'fast food'? McD's is fast, it's cheap, and it offers something that tastes good to me (fillet of fish), so I continue to give them my money....
Harry said…
CarbSane said "Really, I don't find fast food all that tasty, but just tasty enough to make you want more. Don't know if that makes sense."

Yes that makes a lot of sense. In Kessler's "The End of Overeating" he shows that industrial foods aren't made to be tasty per se, but 'more-ish' (this is the scientific use of "highly palatable"). Vendors don't really give a rat's if you like their food, so long as you keep coming back for more!

A perfect example of the contrast between tastiness and more-ish-ness can be observed with most people's responses to a mango on the one hand and a packet of cheese crisps on the other. Most claim that the mango has the better taste, but almost all find that the cheese crisps are harder to stop eating.

That's the genius of engineered food...it actually sucks in almost every measure...but we still get hooked into eating more of it!

Anonymous said…
For that mango, you get fiber. And sugar. It probably IS more satisfying than those cheese crisps....

(but I guess it's whatever you happen to crave at the moment)
Mirrorball said…
"The idea of eating just to satisfy hunger is something I WISH I could do."

Maybe you would be able to do it if you weren't eating fast food and your home-cooked meals were lower in fat and salt, ie, grilled chicken breast instead of sausage fried in oil.
Anonymous said…
@ Mirrorball,

There is 'eating just to satisfy hunger' and then there's eating to please one's tastebuds, share meals and traditions, participate in celebrations, etc.

I'd say you can do both, if it weren't for the 'just' modifier. That really kills it.

I seriously doubt that I would be able to eat 'just to satisfy hunger' if my home-cooked meals were lower in fat. I would be cooking for someone else's tastes, not my own. As for eating fast food, I've been able to lose weight (and continue to lose) despite the fast food in my diet. I do leave McD's with just one fish sandwich.

I wish I could eat just to satisfy hunger. That would be equivalent, in my mind, to eating to live, not living to eat. But there you are: both my husband and I are raging foodies. And he's a great cook. So am I! We do live for many things, but to eat is one of them....
CarbSane said…
Just to be clear, I don't mean to imply that fast food is necessarily "fattening", just that in general it packs a calorie punch vs. food made from scratch and whole foods.

Hubby and I are foodies too. But for some reason I feel no compulsion to overeat our creations. Even though our fare is "whatever fat" - e.g. I drain grease from beef but 85% is the leanest I'll use - our bolognese sauce has fewer calories (I figured it out once) than the sauce we used to get from a local pasta chain.

Tonus that's a good point too. Whenever I do go to a FF place I order a sandwich and smallest size fries (don't get me started with the fact that this is sometimes called "medium"!) and they ALWAYS ask if I want the meal. That will usually include a size larger fries and a soda for a pittance more. It's tempting.
Anonymous said…
It's a nice trick, the way they always ask if you want the meal. Also, that cliche, 'You want fries with that?' is something I don't hear much anymore (they repeat back my request, and then say, 'Will that be your order?')

McD's has extremely cheap fish fillet sandwiches now and then. $3.33 for two. I get that because, yeah, they've suckered me in with the price. But I give one to a friend who's been strapped for cash for a while now, and she always welcomes getting McD's when food is one area where she economizes.

At our house, we cook 'all out' when we cook. I've decided to call cooking our hobby.
Tonus said…
I don't think anyone's a sucker for taking the better deal. :) And I understand the motivation for offering combo deals and discounts and promotional items- if you sell more merchandise, you make more money. It is, intentionally or not, designed to provide you an opportunity to consume more calories (perhaps a lot more) than you might have intended.

I almost never visit fast food places, but when I do I usually eat quite a lot. But that probably isn't due to the marketing and special prices or offers... I just really like burgers and fries and soda. >.< With the changes I've made to my diet and eating habits, my trips to such places will become even less common.
Harry said…
@ eulerandothers

You said "I seriously doubt that I would be able to eat 'just to satisfy hunger' if my home-cooked meals were lower in fat" and "I wish I could eat just to satisfy hunger. That would be equivalent, in my mind, to eating to live, not living to eat. But there you are: both my husband and I are raging foodies. And he's a great cook. So am I! We do live for many things, but to eat is one of them...."

A couple of things:
(1) It could be that your daily food choices (highly palatable, "more-ish" foods) are actually driving your idea that you couldn't successfully eat any other way. You're in a 'chicken and egg' situation...is it your preferences driving your food choices or is it your food choices driving your preferences? Kessler's "The End of Overeating" makes a persuasive case for the latter.
(2) My wife and I are also raging foodies (we're massive fans of French pastry desserts)...we spent all of our 20s being foodies and fat, and all of our 30s (we're 35 now) being foodies and lean (I'm a nutrition and physique consultant, so I maintain sub 10% body fat all year around for vanity and business purposes). What made the difference? One word...FREQUENCY.

In short, unless you're happy to struggle with powerful appetite urges every day, the best way to deal with more-ish food is to limit the frequency of consumption. It's the daily feeding of the cue-stimulus-reward cycle that reinforces and amplifies appetite and food preferences, not the sporadic, or infrequent indulgences.

Bottom line, you can have your cake and eat it too...as long as you don't eat it too regularly.

Anonymous said…
@ Harry,

It's my preferences driving my food choices. I know how to cook food that is lower in fat (and lower in calories). Cooking's my hobby, right? I try to judge the food on the basis of taste - my taste - and I'm not trying to change my taste (I have tried that approach in the past). I watch calories instead. I fit the high calorie food into my diet. It's do-able. I do it.

I don't struggle with powerful appetite surges. But if I'm hungry (as I was today when I had to make a train and skipped grabbing some 'fast food' in the station because I didn't have time), I regard hunger as a minor discomfort. I pack some bran cracker and water in my purse and haven't had to use them yet!

I had just left the hospital where I visited someone who is being fed through a tube. 'Starving' is hardly something I use to describe myself if I am ever hungry at all. If anything, my kitchen pantry and refrigerator are bulging with food. There are REAL starving people somewhere. Not in my house.

If I'm hungry, I eat. I just make it fit into my caloric allowance for the day. If it is high in calories, so be it. Later, I will eat lighter - and if I can't, the excess calories go into the next day's allowance. I start the next day with that (and some good memories of the previous day's meal).

This is how I have my cake and eat it, too. It's how I have been losing weight. Having tried all the other diets (including Atkins!).

I don't like sweet stuff - I just don't 'get' desserts - but when I started this 'diet,' (doesn't have a name, maybe the 'watch the calories diet') I decided I'd never regard foods as off limits. As far as individual foods and food groups go, there are no restrictions. I had a few pieces of pizza (from a local pizza parlor) a few weeks ago. And survived that, actually losing weight that week! I made an effort to eat less the next day.

Bottom line, you can have your fish fillet sandwich from McD's and eat it, too. And regularly. It's a decision, one part of the caloric intake for the day, how to manage the rest of the caloric intake, not going over the limit, is the follow-up...!
Harry said…
Yep, deliberate calorie restriction (with little/no food-choice restriction) can work for sure (it's the basis of Weight Watchers, which has some success with some people).

I find with my clients that this approach tends to work best with those that are pretty heavy (and therefore have quite a lot of 'room' in their daily calorie allowance). For lighter clients (women under 65kgs and men under 75kgs) it doesn't work too well.

The reason being, if you're a sedentary 65 kg woman on say, maintenance of 1800c/day, that's about 500c/meal (which allows 300c/day for drinks, assorted handfuls of snacks etc.). That is NOT a lot of calories if you're eating high fat foods (e.g. one McDonalds large fries has 500 cals...before you've eaten taken one bite of your burger, you're done!).

For such cases, a lower energy density approach usually works best.

It's quite common that clients will use one approach to approach normal weight, and then switch to a different approach to get leaner.

But, if it's working for you, and you're not obsessing about food all the time...then by all means, do it French style!

CarbSane said…
Interesting discussion!

Personally, if I'm going to go Euler's route, I'm not wasting calories on fast food - OK maybe McD's fries 8) - it wouldn't be *worth the calories* for me.

Sounds like you've got a working plan euler! Congrats!!
Anonymous said…
@ Harry,

I'm glad you mentioned 'sedentary' and size. The older I get, the more I think age and sex are in that mix, too.
Sanjeev said…
I've been thinking how this fits in with, among others, the Hall & Chow model of food wastage accounting for the "obesity epidemic". If we assume both theses are true, then the problem is that fast food is the cheapest, any excess would have done the same thing, but it just so happened that the excess cheap production that actually happened was industrial / fast food, not home-made.

This also reminded me of an interview I heard with a nutrition researcher some time ago (can't find it now ) where he claimed most of the fast food incursion was complete by early 70s, with incremental or asymptotic changes (fractional terms, not absolute amounts) since then. His point was, since the alleged epidemic begins in the 80s, something else happened after the ubiquity of fast food. Maybe that something else required fast food to work, but by itself fast food didn't do it.

My searches did yield maps showing consumption of various things (meat, colas, etc ...) and obesity across the US, but the maps were only for rural US counties and included no timelines.

The closet matchup for obesity was with soft drink consumption not with number of fast food outlets.
CarbSane said…
@Tonus: My parents' generation grew up in wartime (WWII) when real sacrifice was required (rations) and whose own parents had gone through the Great Depression. Therefore they put a high premium on value and economy.

Many in my generation - overtly or subconsciously - were instilled with value-seeking and guilt for wasting. The fast food combo meals and such appeal to this very well!
CarbSane said…
Sanjeev: Whoever that was must be using some isolated statistic. In the 60's and 70's you didn't have huge malls with food courts, 24/7 "burger row" fast food lanes in even smaller towns, etc. just didn't exist like they started to pop up in the late 70's and 80's. - Lots of areas wouldn't have a McD's and a Burger King too close in proximity, now it is not at all unusual to see a McD, BK and a Wendy's all three in a row along with a sandwich joint, KFC, Taco Bell, etc.etc. Jared hadn't yet discovered Subway skyrocketing their sales.

Not to mention the other fast foods available in your grocers freezer. Microwaves were not. in every home and office until later in the 80's.
Mirrorball said…
This comment has been removed by the author.