My problem with palatability is mostly that it's treated by Guyunet as an alternative hypothesis, and the insulin hypothesis gets swept aside. I hypothesize that a structure got blown over because it wasn't sturdy/well anchored enough, you suggest that the wind was too strong. Neither of our arguments make sense, the structure wasn't sturdy/well anchored enough to resist the strength of the wind.
Also--eat 1000 calories as butter, hard to finish. 1000 calories of plain potato, also likely to be hard to finish. There will be exceptions to both cases, but that's my point. Both intakes pose threats to homeostasis, the body's response to ensure that excessive amounts of these two different foods will become unappealing is going to be different. With potato, just about all the body has to "worry" about is excess glucose. Insulin response will be pivotal. With plain butter? It's going to be different, whatever hormonal etc. response discourages further intake, it's going to involve much less insulin. There are gut hormones, peptides etc. that affect appetite/satiety, there's some overlap, but a different response depending on the macronutrients in the food.
Suppose the average person would be grossed out at the same calorie level for plain potato as for butter. Maybe that's the way things should work, I doubt it. How about when things break down? How likely is it that these different homeostatic responses will break down symmetrically?
I find peanuts and cheese very palatable. If I'm eating more ketogenically, I can fit small amounts of peanuts and cheese into my diet. Say it's Christmas or somebody's birthday, and I eat too many carby, sugary treats. I might have been eating an ounce each of cheese and peanuts for a couple of weeks previously--after that holiday carb up, I won't be able to trust myself with those foods until I've been eating a stricter diet for at least a couple of days, depending on how extreme the excursion was.
I'll still like foods like cheese and peanuts when insulin is low, I just won't crave them. It's not just a matter of insulin being low--because if I fast, craving and binge tendencies go up. What seems likely is if insulin is low, and at the same time I am well-nourished, then cravings go down, both need to be true.
Paying attention to insulin makes paying attention to palatability more effective, and vice versa. For me it makes some of my favourite foods conditional no-no's instead of outright forbidden.
Insulin, the hormone essential to all mammals for controlling blood sugar levels and a feeling of being full after eating, plays a much stronger role than previously known in regulating release of dopamine, a neurotransmitter that helps control the brain’s reward and pleasure centers, new studies by researchers at NYU Langone Medical Center show.
“We found that when there’s more insulin in the brain, there will be more dopamine released, not less,” says study senior investigator and NYU Langone neuroscientist Margaret Rice, PhD. Her team’s new findings from laboratory and behavioral studies with rodents are set to appear in the journal Nature Communications online Oct. 27.
Rice says the experiments she and her colleagues conducted not only reaffirm that insulin helps trigger the reuptake of dopamine when insulin levels rise, but also are the first to show that the net effect is a rise in dopamine levels. The results may also be the first to demonstrate that insulin’s role in the dopamine pathway may affect and explain food choices.
Excessive dopamine release-->food intake, I like to look at this more as a resistance thing. I did a fast once, ended up binging on fairly bland food (oatmeal) when I broke it. Ridiculous how good that oatmeal tasted. I've seen vegan fasting advocates give "ability to enjoy simple, wholesome food," as a benefit of fasting. Even a vegan diet becomes highly palatable. How about if you're resistant to palatability? That is, it takes more "palatability" to trigger a pleasure response. There's always room for dessert... you might eat less of bland foods. Leptin lowers sensitivity to a sweet taste. This might work to make an apple less palatable, especially if it wasn't that sweet to begin with. It might make a marshmallow more palatable, since it might actually seem too sweet for a person who's more sensitive. People say you can't overeat apples, or at least that people generally won't. This was true for me at 190 pounds, I'd barely want to finish one. If I'm into the 150's--experience shows me that yes, then I will binge on apples.