Your diet does make a real difference, more than you credit for in your reply. In university I had pizza almost every day for a month, I gained 15 lbs (7 kg) and had a way flabbier stomach. I stopped doing that and tried to eat healthier, incorporating salad with my meals, and in just about a week I started noticing it going away, and I was back to where I was before in 3 months.
It wouldn’t surprise me too much to see how a body would react noticeably to a drastic change from a sedentary, highly processed carbohydrate diet and lifestyle to an active, more balanced one. Everyone’s body is different of course so it won’t always be the case, but to me the OP’s claims seem far from impossible. Japan still has its share of oily foodstuff, but the average portion is tiny compared to the US.
Cool, all of that within a week?
There is no chance there is a visible change from a week of eating salads, no matter how fast your metabolism is.
I can lose 10lbs in 3 days if i quit drinking beer. 10 lbs is definitely noticeable. It’s definitely not a real change, just not being super bloated, but noticeable.
An average male adult will burn round about 2000kcal/day, which comes down to 2kg of fat per week (that’s 4.4 lbs in freedom units). To burn through 10 punds in three days, you’d have to finish an Ironman every day. And all that’s assuming that your calorie intake is zero, nada, niente. So if you’re loosing 10 pounds in three days, you are either an exceptional athlete or you’re just peeing a lot. That’s also the problem with all these “loose 10kg in 2 weeks” diets: What you’re loosing is water, not fat. And as soon as you end the diet it’s a matter of days to regain that weight .
If you look at yourself regularly and pay attention you can see your body change pretty rapidly. I’ve specifically watched my body bulking up on its own before burning those stored calories to build muscle and there’s a clear cycle of noticing a bit more pudge a few days before I suddenly make a big jump in cycling distance or how much I can lift (and the pudge also goes away at the same time)