When somebody loses weight, where does the fat go?

I highly recommend a meal tracker app for anyone who's looking to lose. I avoided it for ages. I didn't want to be "one of those people". I felt like I ate fairly well and was working hard enough, I shouldn't have to stoop to that level.

I started bike commuting over 3 months ago now, but my weight was only increasing, and I was pretty sure my diet was the same as ever -- healthy breakfast, fairly healthy lunch, healthy dinner -- mostly homemade, rarely eat out, etc. My only real "sin" was drinking, but it didn't seem to matter if I drank every night or cut back to weekends only (which I had when I started biking, working out more, and again seeing no real benefit).

So I finally broke down and started using one a few weeks ago and it's made all the difference in the world. The biggest advantage is the immediate metrics. I HATED the idea that I could work my ass off for a week or three and see my weight go up, or down, and really have no idea what was happening on a day to day basis. By tracking my meals (plus workouts and commuting between Strava and Apple Health sync), I can immediately see if I'm ahead or behind. It's the feedback I had been craving for years. Where I thought the point of one of these apps was to try to learn what's healthy to eat and to be calorically restrictive (which was unappealing.. again, I don't want to be "that guy"), it's really the realtime data that's useful.

In my particular case, I've learned I actually eat amazingly well for the most part, and it's very easy to run huge caloric deficits during the week. Without even trying I was seeing a deficit of perhaps 1500kcal/day (during the week). What was killing me was beer (on weekends, but then again, 3/7 days is almost half the days of the week) and the occasional big consumption day. You know, have a big breakfast on the weekend, a big lunch, some drinks, and pretty soon 1 day could almost kill a whole week's progress. The tracking has given me the ability to say actually, yeah, one more beer really WILL push me over the edge from a deficit to a gain. I don't really need that 3rd bagel. And so on. And given that I tend to consume more on weekends, and typically I only got a single short run in one weekend day, those weekends were just killing my progress.

On the other hand, it's made me mind snacking a bit less -- the deficits I run during the week are so big that a couple fun size bag of Skittles (we just ran out of halloween candy at work) make almost no difference in my daily progress.

I'm just starting out with it, but again, the realtime feedback has made me realize how much EASIER it's going to be than I ever expected. When I felt I had nothing left to easily cut or change, I actually found the solutions were far easier than I realized, and it's helped me to quantify things that I knew were bad but didn't really appreciate the magnitude of.

And because I no longer have to just "do my best" or a month and hope it shows up on the scale, there's no more disappointment/discouragement.

Not worth it. If you excercise hard for an hour daily you can triple your rate of breathing during that hour. So you get 26 instead of 24 hours of usual fat burning.

Not much of a difference. Skipping some food can do much more.

It's pretty difficult to double that number. Can you really double your metabolism without ill effect? Or without massively changing your lifestyle?

The normal expectation is maybe 10-25% change. Any more than than would require things likes 8 hours of exercise per day.

I did similar a few years ago. Dropped from 172lbs (78kg) to 139lbs (63kg) in 5 1/2 months. Near 21% weight reduction in body weight, just by counting calories and walking (granted, quite a bit). There definitely isn't a "wall" you encounter when losing weight. I tracked everything I ate (often to the gram) and it felt like little more than basic arithmetic.

Had a friend take notice, so he took it up himself. Dropped the best part of 60lbs (27kg) over the course of the year. Very different diet, but again tracked everything he ate (again, often to the gram) and lifted weights instead of walking. He was baffled with how simple it ended up being, but was pleased with himself nonetheless.

The mass that's converted to energy in both chemical and nuclear reactions comes from differences in bond energies. Nuclear chemistry is about the bonds between subatomic particles, ordinary chemistry is about the bonds between atoms.

Mass-energy conversion isn't a special thing, it's universal. All energy has mass. When energy moves, mass moves, always.