Today saw a new low of 140.4, which is a good sign. It's about time this train got moving again. When I showed my boyfriend the flatline of the past couple of weeks, he said "well maybe that's just the weight your body wants to be when you're fit and working out." I said maybe if it doesn't budge for another month I'll consider that hypothesis, but I think it's just a plateau. My reasoning is, at the beginning of January my estimated calorie balance was pretty much in line with my actual weight loss. If the flatline was a reflection of my "really" maintaining, my burn rate would have had to drop to at least 300 calories less than what my formulas predict, in just a few weeks, with no unusual metabolism-affecting behavior on my part. I find that implausible.
It's actually really fascinating to me, why different people have stable or unstable body weight, where their most stable body weight is, and how much ease or difficulty they have in changing it. There's set point theory, which is supported by numerous studies of generally two types. One type is conducted on normal weight people who are put on either low- or high-calorie diets; they tend to lose or gain less weight than expected purely from calorie calculations, and also vary within the sample in ways consistent with their family history as to how much weight change is experienced and whether muscle or fat is affected. The other type of study is conducted on moderately obese people who are put on a diet, and the usual result is that they can lose about 10% of their body weight and then stall out, either because they start getting too hungry to stick to the diet, or for no clear reason even though they are continuing to comply. One flaw with some of these studies is that they put people on extreme diets suddenly, which will of course have metabolic effects, but others make reasonable changes and still get the same results.
Then there are the common and not-so-common situations that really throw that whole idea into question, or at least demand a better understanding of how a set point is set. There are extreme examples like Jennette Fulda/PastaQueen, who became almost 400 pounds and then lost half her body weight, or Jessica Smith who similarly was very fat and then slimmed down enormously. Then what about the "freshman 15" effect? If body weight is more or less hardwired, then why do so many people gain weight when they go to college - why don't their natural hunger mechanisms compensate for the different environmental conditions, say, causing them to eat lightly the day after a pizza party? Why do some people seem to gain weight at much more than the typical pound-per-year rate, piling on the pounds until they reach a psychological breaking point, and always have trouble maintaining a weight loss even if they previously were stable for a time at that weight? Why has my boyfriend's weight been stable plus or minus 2 pounds for years, whereas mine has been more like plus or minus 15? And why has it been so easy for me to lose over 40 pounds? I'm now almost 10 pounds lighter than I ever was as a teenager, 25 pounds lighter than my most average weight, what you might have called my apparent set point, and I'm feeling no backlash. I am still pushing typical deficits of 300-600 calories, and I'm not killing my life with exercise or white-knuckling against hunger. How do you explain that in set point theory?
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