Is Junk Food Making You an Unmotivated, Lazy Couch Potato?

Food choice matters. Period.

Now, I'm well aware that calories matter a whole heck of lot. A surplus of calories from whole foods could very well make you just as fat as a surplus of calories from junk; however, in the case of the former, you would have to intentionally overeat to put on pounds, while in the case of the latter, you would have little trouble eating to excess. It is for this reason that ad libitum whole food diets (such as paleo and its many, many variants) work amazingly well for hassle-free weight loss. The foods on such diets are simply far more satiating per calorie in comparison to a diet mainly comprised of Micky D's, Hostess, and Doritos.

This is not so say, however, that you cannot lose weight by eating junk. Mark Haub, professor of human nutrition at Kansas State University, demonstrated the possibility of doing such a thing via his "Twinkies diet," whereby he lost 27 pounds in two months, all the while comprising up two thirds of his daily calories from junk food.

But, the fact that you can lose weight by eating a lot of junk does not prove that you should. The foods that we eat are more than just calories. Moreover, the foods that we eat are more than just their respective quantities of protein, carbs, and fat. 100 calories from a plain boiled potato will have a significantly different impact on you in terms of satiety, nutrition, and metabolic response, than will 100 calories from a sugary soda.

I'm sure, however, that you're already in the know about such things. So why then am I seemingly ranting on and on to the choir?

Because I'm making a rather feeble segue into discussing a recent study which suggests that food choice may effect your brain's motivational response to rewarding stimuli.

The Study

Researchers from UCLA tested the physiological and behavioral effects of two different diets on rats--one diet was "healthy" and the other was full of junk. 

What did the researchers discover?

No motivation to find a cone?

The rats that were fed the healthy diet--comprised of complex carbs and whole foods--remained relatively healthy. The rats that were fed the junk food diet--comprised of highly processed, sugar laden foods--weren't so lucky. Not only was the junk food group fatter than their whole food counterparts, but they also experienced reduced motivation; thus inferring that the junk food may have altered the psychology of the rats.

The researchers found that the junk food group responded more slowly to, and required more rest to complete familiar cognitive tests, such as pressing a lever to receive water or food. In the researchers' own words, this group of rats seemed to be suffering from "cognitive impairment."

At the six month mark of the experiment, the researchers reversed the diets of the two groups. 10 days after the switch, little change was observed between the two groups; revealing that well-developed habits, as opposed to short term dietary changes or eating sprees (Thanksgiving comes to mind), are what most impact long-term trends in behavior and motivation.

One of the study's researchers also indicated, in regards to the data--

Point Proven!

"We interpret our results as suggesting that the idea commonly portrayed in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause, rather than an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue."

In other words, if this data regarding rats is at all applicable to humans (which it might), then we need to seriously reconsider some of our first impressions of overweight or obese individuals. It may be that poor food choices lead to a lazy lifestyle; not the other way around. We might represent the progression like this--

Junk Food--> Laziness--> More Junk Food--> Eventual Obesity

I'm admittedly making a rather obvious generalization here, but I think this generalization is much less cruel that the stereotypical model that says laziness is the cause of obesity. However, once one becomes habituated to being lazy and eating junk, I would argue that a feedback loop develops; one that can only be broken by finding the motivation to break this cycle--a cycle that is partly comprised of a lack of  motivation. You can see the difficulty here.

Coming Full Circle

Hence, we now return to my original statement at the beginning of this post: Food choice matters. Period.

Though you certainly can lose weight while eating junk, good luck maintaining the motivation and the will power to do so!

*If you want a comprehensive explanation for why an obesity "epidemic" is afoot, check out this resource from obesity researcher, Stephan Guyenet. It's rather dry, but incredibly informative.