> But exercise has very little effect on weight compared to diet. It's a known fact, even for the fans of counting calories.

I recognize that this is conventional wisdom, but it hasn't been borne out by my own results losing well over 100 pounds / roughly 40% of my body weight over the course of several years.

I've counted calories strictly, with the same methodology and same limit, and documented weight regularly, both during low-activity low-altitude winters and medium-activity, high-altitude summers. The results I got, over the major windows in which I got them, were as follows:

altitude | activity | loss | weeks | lbs/week | implicit daily caloric deficit @ 3500 cal/lb
high | high | 60 | 14 | 4.28 | 2140
low | medium | 0 | 6 | 0.00 | 0
low | low | 17 | 22 | 0.76 | 381
high | low-med | 47 | 30 | 1.57 | 783
low | low | -2 | 22 | -0.09 | - 45
high | medium | 10 | 4 | 2.50 | 1250

I'm defining "high" activity here as "regularly exercising to physical exhaustion", "medium" as "regularly climbing up hills that cause me to breathe heavily but don't exhaust me", and "low" as "regular walking but nothing that strains my body meaningfully".

This is now data collected over years of weight loss and multiple seasonal changes in location and activity, and I find it difficult to explain this within the context of standard weight loss advice. Exercise at altitude seems to burn far more calories than it "should", by a factor of four or five times.

I walked a mile or two every other day on average across this period, meaning the only difference is a roughly 15 to 30-minute walk up a steep slope roughly every other day. A typical calculator will tell you this "should" burn on the order of 100-150 calories, but the data suggests it's closer to 500-1000.

I'm not a doctor, so I don't know why this is. I've largely ruled out:

- Diet, which is conserved across locations fairly well (I cook most of my own food using widely-available ingredients)

- Seasonal effects, unless they happen to produce very sharp discontinuities at the exact time I relocate each year

- Emotional state, since these results have been robust to both positive and negative emotional states in both locations

- Temperature, which is near-constant year round (because I live in warm places in winter and cold places in summer)

- Groundwater, because I drink almost entirely bottled water and not local water supplies

- Major underlying medical causes (my bloodwork is great and I don't have any reason to think I'm sick)

I have a working hypothesis that the studies that established calorie burn from exercise (which I believe largely did it by measuring CO2 exhalation) were missing a great deal of the actual energy cost, because the costs of anaerobic respiration take place over hours following exercise and not just during it. But I also can't imagine people with actual medical expertise haven't thought of this before. A negative correlation between altitude and obesity rates is well-established, so something is going on.

In any case, the data is the data, and it points very strongly towards altitude and exercise, synergistically, being almost exclusively the source of my own weight loss.