Satiety, Potatoes, and Chicken Breeds
the food reward hypothesis is bogus
In his article discussed in the previous post, Dr Christianson recommends plain, boiled, cooled potatoes as the most effective "hunger blocker." It's important to recognize that this article can't be taken in isolation and must be seen in the functional medicine/paleo discourse in which it was written, no matter how mainstream an audience he's reaching for.
To which point, as I already hinted, you can't mention plain, boiled, cooled potatoes without bringing up the food reward hypothesis and the concept of resistant starch (separate but related).
The "resistant starch" hypothesis, as I said already, suggests that this particular kind of fiber is fermented by gut bacteria into short-chain fatty acids, highly satiating. But this begs the question whether a given person harbors the appropriate bacteria. Some would say that eating resistant starch will attract colonies of these bacteria, but in the meantime, depending on your bugs, you could get horribly bloated and gain weight. Even if you think you'd like some of those bacteria, this isn't good short-term weight-loss strategy.
Food reward. Basically, the food reward hypothesis claims that the better food tastes, the more of it you'll eat--and, the implication goes, the more you eat the more likely you are to be in positive energy balance and gain weight (false: you could very possibly be more active after eating more calories, for example, or blow through a bunch of energy doing some hardcore math or writing, not to mention that happy chemicals burn calories).
There are so many things wrong with this hypothesis/claim:
- First off, it implies that those people who do get fat (since, obviously, not everyone does) are gluttonous and deficient in willpower, thus perpetuating a reprehensible cultural meme.
- It takes for granted the simplistic notion that whoever eats the most gets fattest. So, the gluttons who have no self control are the ones who everyone else gets to despise. Again, this is completely false. A simplistic counterexample to this simplistic notion: Lou is 21 and a college soccer player; Ashley is 67, type-2 diabetic, and sedentary. Never mind confounding details like their genders; you can be sure that Lou is leaner than Ashley, and I'd be willing to bet that Lou eats a lot more than Ashley too. In my observation, activity level correlates to caloric intake far better than fatness. In other words, people who are very physically active tend to eat a lot. People with high bmis? Some eat a lot, some don't. Sort of like people with average bmis.
- It's not controversial that "mono diets," where a person only eats one food for a period of time, lead to spontaneous reduction in amount consumed. This single item can be potatoes, or it can be twinkies. This phenomenon of "getting bored" with the food and so eating less isn't necessarily a behavioral issue, though. All foods contain toxins, and the body's systems are going to shut down desire for any given food after a certain point.
- The better a food tastes, the sooner a person is satisfied by it. Bitter herbs have been used for millennia, in many different herbal systems, to enhance sensitivity to the taste of a food and thus regulate and reduce appetite. Conversely, people with conditions that dull their taste buds tend to eat more.
- On the other hand, the Pringles "once you pop you can't stop" scenario is real. Foods designed to be "craveable" (yes, they had to come up with a word for it)--foods designed to make you less rather than more satiated, so you'll eat more (how illogical is that?) are being designed by scientists in labs. These foods are optimized for sugar/fat/salt (carb+fat together=more fattening; too much salt can conversely desensitize taste buds), laced with chemicals, and designed to be maximally beguiling through textural and visual cues too, let alone canny marketing. They then get called "maximally rewarding." Guys, this isn't reward. This is excitotoxicity. When a food tastes really good, you don't need to keep eating more and more of it. The food reward hypothesis confuses reward with excitotoxicity.
So, where's the reward in "food reward"? Let me tell you a story about the chickens who freely roamed one of the farms I lived on in Hawaii. A small cohort of these chickens showed up at my cabin early every morning to see what might be good. They were Rhode Island Reds and White Leghorns.
It was fascinating to me how the different breeds differed in what they were willing to eat. It's true, the Rhodies, who ate a greater variety--they were helpful in eating up the endless earwigs, for example--were bigger than the pickier Leghorns. Someone said the Rhodies ate more because more things tasted good to them, implying gluttony again. (Food reward for chickens? Another nutrition just-so story. I don't think birds atually have taste buds.)
But here's the other truth: the thin Leghorns across the board were stupid, and the Rhodies were noticeably smarter. Despite their pickiness, it was a Leghorn that got hold of and swallowed a worm-shaped rubber fishing lure and could not be dissuaded or tempted (with some real food) to drop it. Stupid, and stubborn.
My point? (And bear in mind this is coming from someone with celiac disease who's also restricted her diet in one way or another (from fruitarian to ketogenic) her whole life.) My point is twofold:
- Applying the concept of food reward to fatness is totally bogus.
- If there is any "reward' to eating a wide variety and quantity of foods, that reward is smartness, as well as greater potential to be active--energy use vs energy conservation.