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Comment by catdog | Hacker News Reader

You also have to do an awful lot of exercise to burn a substantial amount of calories.

Every day the human body burns a substantial amount of calories just being alive. You have to simply not eat insulin-raising bullshit for a couple days, and start eating less or even fasting so your body starts burning the bodyfat it's been storing all that time. Worked for me (-8kg in approx 2 weeks) no exercise involved..

I ran 16 miles this morning, burned over 2000 calories. But I won't lose any weight, I am going to eat those calories right back.

That is indeed a substantial amount of exercise! Awesome work.

In a thought experiment (where it's possible to know the exact amounts) -- do you think consuming exactly 2k kcal is perfectly even with burning exactly 2k kcal? IE, is there overhead to transform the energy? Does it account for physical/energy waste?

I don't know, anecdotally it seems that if I spent X calories exercising, my hunger will adjust until I consume roughly X extra calories.

The energy expenditure does account for waste, I think only about 20-25% of the energy spent is turned into mechanical output

I have experienced the same issue when I burn larger amounts of calories. I've found burning about 500-800 calories (I run for about an hour) at the end of the day some time after dinner is my sweet spot.

2000? The standard estimate of net calories burned (cals above basal rate) is 0.98kgkm (i think it is 0.98, i usually round up to 1).

You might enjoy this: http://theoatmeal.com/comics/running

That should read 0.98 × kg × km

0.98 x 73 x 25.75 = 1842 kcal, not too far off

If there's any exercise that has helped me shed weight, it's hiking. By being moderately active throughout the whole day you easily burn an extra 1500-2000kcals. Jogging has never really helped in shedding weight for me, just general fitness.

How many hours per day do you hike? You probably have to hike for an hour to offset just one chocolate bar.

I'm talking about proper hikes I do on the weekend. Like 6-10h. That's 6-10 chocolate bars, and I don't eat that much on these hikes.

Considering hiking is mostly walking, and calorie burn rates are dominated by distance, I'm guessing between 30 and 50 km? You generally burn about a quarter of what you would above basal metabolic rate per unit time walk versus running. So this would be equivalent to about a 1:30 to 2:30 run. Its very good,but certainly isn't at the level where you get to ignore food.

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