Calorie estimates are just that. On the one hand, calories as measured by burning might not line up with the body as much, and different people use different amounts of energy. I think Sam was probably the hardest hit, being that he was the youngest and seemed least fit. Lucas's body would be able to handle it better for a while as he is more used to cleanses I'd think with his natural therapy background, but he'd have less overall reserves. Allan probably had the best combo, older guys who are healthy-ish have enough fat to keep them going for a long time, and are physically able to adapt to low-calorie more easily. Young guys, the body is in grow mode. Most of this is mostly made up, but it sure sounds logical. Sam should have gotten on to getting more food sooner, more traps, more tries. Haven't seen the post-special ep yet.
Lucas probably weighs 160 lbs or so and 2200 calories is an estimate based on city life where the body is in rest mode/light exercise. Of course it's an estimate but that does not mean there is possible variance of thousands of calories (it would be a few hundred at most). Hiking with loads, chopping wood, building structures, etc. can easily require 400-600 calories an hour, and generally increases your metabolic rate throughout the rest of the day. His fasting rate would be approximately 1600.
That's an important consideration because it may be better in a situation like this to eat all at once and then fast. Anything over 500 calories a day (Kochanski seems to argue 0) can increase your chances of starvation if you're not meeting the daily requirement. This is because of the 500-700 calorie difference between normal and fasting metabolic rates as well as the increased effort involved in acquiring food. If we say there is an average of 4 hours of work per day while at the normal rate then we have an approximate 3400-4600 calorie requirement as opposed to the 1600-2000 expended while fasting (assuming less than an hour of work). Which means that unless you're getting double the food you normally eat you are better off fasting.
That would be 600 snails or 35 crabs for a 4200 calorie day. A salmon or two would be much better in a lot of ways. And no doubt on those days where Lucas was building a cabin, boat, yurt, etc. he was going through 4000 calories or more. (He also got sick after his feast which they didn't seem to follow up on.)
jonny, your example does suggest that the 2200 figure is misleading. Losing 41 pounds in 30 days is a dangerous level of weight loss, and these guys would be burning more calories than you did on your diet. When I lost my weight I went down 60 lbs in 3 months, but I was also eating over 6000 calories most days with 2-5 hours of heavy/extreme exercise.
As an estimate we could suggest these calories:
-2200 +0 (start)
-1600 +500 (fast with minor nutrients)
-1600 +3000 (fast with big meal)
-2200 +1600 (off fast with average meals)
-4200 +1000 (heavy work with little meal)
-3600 +4000 (heavy work with large meal)
-3000 +0 (sick)
That would mean 8,300 calories lost for the week and 2-3 pounds. Just an estimate, but consistent with what we see in a lot of these shows with massive weight loss.
The short version. Just one day of hard work per week can increase the base rate of daily calories by an average of 300, or more than 10%. That is very significant.
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