I'm not following your point.lessthanhalf said:
I don't believe every carb affects appetite or hunger the same way. Potatoes get labeled as high glycaemic index, yes, but they also carry very little energy per unit weight — especially the low carb varieties, which sit around 50 kcal/ 100 grams. That makes it genuinely difficult to pack away a huge calorie load from them. Consider that half a kilo of potatoes amounts to just 250 kcal, provided no oil or fat is added. By contrast, 3 slices of bread delivering a comparable carb calorie count go down far more easily and quickly, and they don't leave you as full. To avoid losing weight on potatoes alone you'd have to consume roughly 2 kilos daily, which is a substantial amount and likely beyond what most people could comfortably manage. With bread, on the other hand, it would be very easy to eat enough to gain weight even if it did not include butter or margarine . And based on what I've experienced, plus some experimental confirmation of this, low glycaemic index carbs by definition cause lower glucose peaks, but also cause far less in the way of sudden dips in glucose afterwards, which is presumably the trigger for hunger, or binge eating episodes. I also suspect that the low calorie density of potatoes blunts how much glucose spikes and then dips, even with a fairly high glycaemic index, simply because volume limits how many calories you take in at one sitting.
When it comes to binge eating and bulmia, I can see GLP's helping through several distinct routes. The early satiating effect would presumably reduce the inclination to keep eating after a certain point. The reduction in food noise would reduce general thinking about food as much and lead to less episodes. And the overall reduction in hunger would reduce the basic drive to eat. As well as the alterations in reward circuitry functions, that are thought to reduce many different types of addictive behaviour would help as well. There is no obvious reason they would help with the purging aspects, except by reducing the binging so it is no longer needed.
Your arguments and the bread analogy all make sense to me, but what caught me off guard was that eating only plain potatoes didn't produce that irritable, hungry edge, whereas a highly processed meal mixing macros frequently does. Unless your point is that a sharp glucose spike by itself can't set off that hangry state unless there's also extra calories involved—whether from that same meal or from what someone's been eating overall lately?