There is a lot of issues I have with this theory. Right now, though, I'll stick to this one. If it is true that you can unlearn the association between nutrition and flavor (a stupid theory IMO) ... what effect would calorie free highly flavorful food have?
We've had fake food for many decades now - foods that taste like they're loaded with sugar and fat but actually are not. If this theory is correct - that flavor paired with tons of energy teaches the body to associate flavor WITH rich nutrition, thus leading to capitalization on that by increasing hunger - isn't it true that drinking diet soda would "break" or at least confound the association just as much as drinking bland oils?
We see from observing dieters this is not true. The more you reduce calories in food, while also loading it with taste sensations that are pleasing, the more people eat. Diet food does NOT teach the body that taste is a poor indication of nutrition, which, in theory, it should.
This implies to me (and it is very obvious) that taste (and it's superior texture) -> nutrition is hard coded
in our genes. It cannot be learned or unlearned, and at best controlled by eating LESS often (like once or twice a day) or from fewer foods (example, a low carb basic diet).
Also, the shangri-la diet seems to be ignoring the fact that oil is NOT a "flavorless food". Even though we cannot perceive a vivid taste, research shows we CAN detect the presence of fat in food through other means. If we reason the smart body wants to capitalize on ample nutrition, and if we recognize the body CAN detect fat as a nutritious substance (it can), then the idea that drinking oil before meals helps you to eat less for this theory
Oh, I don't doubt eating oil before meals helps you to eat less at meals. But, it's quite simply only because FEW substances reduce the rate of gastric emptying, blood sugar response, and increase satiety the way fat does. If the shangri-la diet recommended an oil and vinegar drink, the results would be even more spectacular because vinegar is both calorie free AND potently cleanses the palate (vinegar, like fat, reduces blood sugar and gastric emptying thus increasing satiety and fat burning capabilities).
Fructose water? That one's strange. All I can assume is that since fructose is extremely low GI, yet also a carbohydrate (thus instant energy), it is a good way to quickly stop hunger and induce a metabolic fed state WITHOUT contributing to the insulin roller coaster that a glucose drink would. Few things quickly take away hunger than a surge in energy before
your body starts cranking out the insulin (and then, once that happens, your hunger grows and grows as lipolysis and GNG is suppressed to near nothingness as you peak with the hypoglycemic episode).
If you go into a meal like that (fed, yet, without risk of dramatically becoming hyperinsulinemic thus hungry later) ... it is reasonable to assume you'll eat less at that meal.
Basically the diet, IMO, is a gimmic. It is a way of tricking you into getting your metabolism to control its insulin and hunger without uttering the unsexy words "don't eat freaking starch and sugar"
. Ultimately, like all fads, it is too silly, the rules too pointless and vague to really work out long term.