Wednesday, February 20, 2013

Causes of Obesity: Food Variety

So I had this new idea today while sitting in class.  We were talking about food palatability and how modern food is "hyperpalatable"... this just means that it is extra salty, extra fatty, extra sweet, and overall just more pleasing to eat than food of the past.  (I've talked about this before 1, 2, 3, 4).  And I started thinking... there are like a million different reasons why Americans are so obese.  Why don't I start exploring each one individually on my blog??  So that is what I will be doing.  Starting now.  Maybe ironically NOT starting with hyperpalatability of food... although it's a related topic.  Today our cause of obesity is unconventional, one you probably haven't thought of.  And you all know how much I like bringing you a fresh perspective and new way to think about something.  So without further ado...

Cause of Obesity #33162:  Food Variety

Why do we eat?  Is it because we're hungry?  Partly.  But there are other reasons too.  Don't even act like you don't know... boredom, convenience, stress, depression, happiness, celebration, social pressures, societal expectations, just because it's meal-time...  the list really does go on and on.  Because of this, researchers have divided eating into two categories:  homeostatic and non-homeostatic eating (1).

Homeostatic eating:  eating is driven by a true need for energy
Non-homeostatic eating:  eating is driven by factors other than a need for energy

Pretty simple really. 

So how does variety fit into this?  Easy.  You can only eat so much of one food.  In fact, variety in food is one of the major factors driving how much you eat, whether you notice it or not.  There are even diets designed for weight gain based around this principle... take the cafeteria diet for example.  Allow humans (or rats) easy access to a high variety of food and they'll gain weight.  In contrast, give someone a restrictive diet that lacks variety and they inevitably eat less and lose weight.

Diets With Excessive Variety
Examples.  Take this 1994 study, which put 10 men in a metabolic ward for 7 days with unlimited access to a wide variety of palatable food, including the following:  "English muffins, French toast, pancakes with syrup, scrambled eggs, chicken pie, cheeseburgers, margarine, white sugar, various cakes and puddings, apples, jelly beans, Doritos, M and M's, apple juice, 2% milk, sodas and several other foods." (2).  These men ate, on average, a whopping 1,544 calories over their estimated needs!  :-o!  They gained an average of 5.1 pounds in just one week.

There are also two similar studies done in Pima Indians, which is a population known to be susceptible to easy weight gain.  One was done with Pima men (3), the other with Pima women (4).  The results, as you would expect, showed that they overate and gained weight at a similar clip to that first study.

Diets That Lack Variety
But what if we restrict our variety?  Well I've written about this before in a post called "Does Sugar Make You Fat?" (5).  In one study in which the participants consumed nothing but a sugary beverage in unlimited quantity, the obese subjects rapidly lost weight.  One subject lost 200 pounds in 255 days.  In another study, the subjects ate nothing but fruit and nuts experienced the same results.  There are plenty more examples of this, like the guy who ate nothing but potatoes (6).  Use your Google machine.

Think about some of the more successful weight loss diets out there, specifically the ones that get you to lose weight without counting calories.  Paleo diet - restricts grains, legumes, and dairy.  Vegan diet - restricts meat and dairy.  Atkins diet - restricts carbohydrates.  30 bananas a day diet - restricts all non-banana foods.  One of the main reasons these diets work is because they inherently lack variety.  You can eat all the food you want and still lose weight, because you can only eat so much of one particular type of food.

The Modern 'Cafeteria Diet' Food World. 
Now think about the food environment we live in today, compared to just 25 years ago before the obesity epidemic.  We live in a globalized world; the amount of variety at your fingertips is unprecedented.  If you live in or near a city, you are just minutes away from any of the following... Mexican restaurants, Chinese restaurants, Thai restaurants, Sushi bars, hibachi, Panera, steakhouses, Italian restaurants, burger joints, fast food, gas station food, sandwich shops, 24-hour diners, bakeries, Starbucks, Dunkin Donuts, all-day breakfast restaurants, chocolate shops, Indian restaurants, liquor stores, pizza shops, and all of the others I'm forgetting.  There are like 200 different types of potato chips at the grocery store, there's a whole aisle devoted to it...  Ain't nobody got time for that!  Whatever you want to eat, you can have it in just a moment's notice.  We essentially live in a cafeteria diet world.  Do you think this has something to do with the obesity epidemic?  I think so.

I  mean just the other day for lunch, I ate enough sushi to feed a family of four... Why?  I hadn't had sushi in weeks; I was craving it.  There are just too many other foods to keep me occupied, just too much variety.  And boy was I stuffed...  but then I had a piece of my girlfriend's apple pie.  See what I did there???  Stuffed on sushi, but there's still room for something else!!  Good ol' variety nipped me in the butt again.

With so much variety, we can't just free-eat anymore and stay thin.  The more variety we're given the more food we're driven to eat.  And I'm sorry... I love variety, probably more than the average person.  I know damn well that variety is the spice of life. As cliche as it is, you know it's true.  But I think this beloved variety is making us fat.

What are your thoughts, readers?  


  1. Where do I start???
    I eat too much because I know I have to diet tomorrow... always tomorrow.
    And if I'm dieting tomorrow, then today I must eat everything I possibly can, even if it's disgusting.
    Then tomorrow I'll be on a diet for an hour or two, then I'll decide that I'm doing it wrong, so I'll start planning a BETTER diet tomorrow.... and because I'm starting a diet TOMORROW, then I have to eat everything possible now.
    It's called restraint theory and the 'what-the-hell' effect... Janet Polivy I think.

  2. ....and, yes, I do agree that food variety is a factor! (Sorry, I'd had a few glasses of wine when I wrote last comment :( )

  3. Hahaha - restricts all "non-banana" foods.

    Definitely agree with you there. I also think that variety within a sitting offers palate cleansing. Last night I went from turkey to chicken wings to kale to raw tomatoes, etc. etc. Fortunately Michael ate all the ice cream, b/c I could've done some damage there.