I haven't read the book yet--but one thing Fung writes about that I'm not that sure of is the difference in the effect on metabolic rate between fasting and low calorie dieting. I think it's reasonable to suspect that there's an advantage, if you look at some of the circadian rhythm studies he wrote about, or at Ludwig's study where metabolic rate was higher in maintenance on a ketogenic diet than on a higher carb diet--because fasting is closer to doing a ketogenic diet than it is to a high fat diet, obviously. But the Minnesota starvation study involved getting participants downright skeletal, to the point where they didn't have sufficient bodyfat stores to support a reasonable metabolism--if their metabolism hadn't decreased to the extent that they did, on the calories they were eating, they would have died. To be fair, you'd have to compare these guys to themselves if they'd been exposed to an inappropriately long fast, to the point of emaciation--in which case, ideally there would be a decrease in metabolism, because its failure would be counter-survival.

NEMarvin--I wouldn't worry, as long as you're still losing significant amounts of body fat. 1400-1500 calories a day and a long stall for a guy your height would imply a very sluggish metabolism, but if you're getting appreciable calories from your fat stores, that's okay. My original experience with low carb was that at my heaviest weight, appetite greatly decreased on low carb--but then as I lost weight, appetite returned again.

Dr. Fung talks about people intermittent fasting, and then only experiencing a 15 percent increase in appetite on their feeding days. This isn't my experience at all--but then I suspect that it might have been when I was at my highest weight. I think there's a reason why very young, very lean men who are trying to get ripped and busy telling people who aren't any of these things how to lose body fat insist that intentional calorie restriction is key--they're already at an ideal body weight, and from there, getting ripped necessitates going past the body's natural mechanisms.

I wouldn't worry about the lowered appetite by itself--unless there's something else going on, like low energy to go about the day's activities, lack of weight loss reasonable to your calorie intake, etc.

I think some of the decrease in metabolism that can be expected with weight loss is sort of relative. When I get down below 160--certainly my metabolic rate is likely lower than it was at 190, on any given diet. But I have a bit more get up and go, I'm more likely to spontaneously break in to a run if I go out for a walk, etc. This is something that's not really captured, looking at metabolic rates on a graph.