Now, if a person goes into P3 with the idea that 'I am used to eating tiny amounts of food now and I'll just eat a tiny bit more - maybe a salad- and maybe I'll lose even more weight!' that person's body will sense the lack of calories right away and that person will GAIN.
Because that person's body will go into 'starvation mode'. What does that really mean? Going long periods without eating causes a dip in blood sugar. And then when some bite of food is eaten, the body overreacts with a big insulin surge. And since insulin is a fat-storing hormone, you end up storing whatever calories you just ate, instead of burning them as fuel. NOT what we want.
What we want, because it will allow us to maintain our LSW, is called glucose homeostasis— a constant blood-glucose level.
I believe that Dr Simeons, had he lived to see all the nutrional information available to us today, I believe he would have concluded that all of us were in a pre-pre-diabetic state, and over-sensitive to carbs and BECAUSE we were able to effect such drastic lifestyle/food choice changes while on the HCG hormone, we were able to stop the raging internal floods of insulin and leptin and ghrelin among others which work together to control hunger and appetite and metabolism.
(Leptin wasn't discovered until 1994, and ghrelin not till 1999. Obestatin, another hunger hormone, was even more recently discovered in 2005. All play key roles within the hypothalimus and are key factors of metabolism. Do we understand these fully yet? I doubt it, but we're trying.)
In P3, if a person is having trouble maintaining, I believe it is one of two things; either they are not eating enough calories (starvation mode=insulin surge when some food IS eaten=weight gain), OR they are eating too many carbs(sugars) in the form of yogurt, nuts, and especially fruit (fructose) (sugars in the blood stream=insulin surge=weight gain). Some people are even doing a bit of both(!) - hardly eating enough and then when they do eat, it's with too much focus on yogurt, nuts and fruit, not enough protein and fat or vegetables. Eat your veggies. The fiber keeps blood sugar stable.
You can enjoy eating your vegetables by making them calorie dense - put the calories on top -
Think brocolli with cheese sauce, asparagus with hollandaise sauce, artichokes too, eggplant and zucchini grilled in olive oil, cole-slaw made with homemade mayonaisse and stevia, not sugar, celery spread with peanut butter or cream cheese, zucchini in olive oil alongside chicken kabobs, etc. When you eat chicken, eat 'Chicken Piccata'! That sauce is 304 calories alone! Or make baked chicken with mozzarella on top! Yum! 170 calories for 2 slices!
Blood sugar. Eating protein and fat helps keep blood sugar stable, and slows down insulin's entry into the bloodstream. If you avoid sugar and starch, you almost totally avoid an insulin spike, almost. But if you also avoid starvation mode and eat less yogurt, nuts and fruits and more proteins and fats, then you WILL keep blood sugar stable. And you will NOT gain.
If you were to start your day without fruit, I think you would have a better day. Fruit contains the simple sugar fructose which sends the body a signal to produce insulin to deal with the sugar load. So you get a spike in insulin, and an insulin spike = weight gain! You can slow down the insulin response by eating fructose (ok; fruit) with proteins and fats, (like an apple with peanut butter) but the higher the insulin spike, the bigger the weight gain. Body builders avoid fructose almost entirely. If we really limit our fruit intake, and ONLY eat it with proteins/fats, such as an apple WITH peanut butter, or strawberries WITH whipped cream/stevia and vanilla - and limit the strawberries to 4 or 5, then I believe we'd do much better. (The best fruit for morning, if you really love it seems to be the ol' 1/2 grapefruit eaten along WITH your eggs and all.)
A large person requires a large amount of calories to nourish that person without he or she slipping into 'starvation mode'. However, it IS possible to eat a large amount of calories without gaining weight, overeating or even feeling 'stuffed' or bloated. Check out my 'Olive oil' post - that's a plan for how to eat 3200 calories comfortably - and that's without coconut flakes, larabars, or creamy Piccata sauce!
So, that's my theory, based on my best efforts to try and understand the 'why' of it all - My sources are The Mastering the Zone: The Next Step in Achieving SuperHealth and Permanent Fat Loss books by Dr Barry Sears, whose original focus was on helping diabetics, and Jorge Cruise's Belly Fat Cure which is all about the hidden sugars in our foods that are making us fat, Gary Taubes Why We Get Fat and What to do About it (maybe my favorite), and Michael Pollan's In Defense of Food (also a favorite)
...and my own P3 experiences, and my husband's, and in participating and learning on the Ketomist support site and also now, as I am trying to learn as much as I can as I try to help my aged parents battle full-blown diabetes. I'm doing loads of homework daily and plan to keep on updating here to share my growing understanding.
I want to get an 'A+' in this. :)