[spicyusername]

    dropping a slice of bread won't cut it 

But it will cut it, assuming you're moving your body the same amount every day. It just may take a while if you only cut a single slice of bread and you're wanting to lose a lot of pounds.

Your body mass doesn't materialize out of nothing. Food in, body mass out. Less food in, less body mass out. Simple as that. Everything else is optimization that's not really required, just eating less, patience and consistency.

[srean]

His point was when you eat more calories than you need, then the body can afford to be sloppy (inefficient) about absorbing all those calories.

When you cut down a little on food but are still above or at your daily calorie requirement, the body can adapt by increasing its conversion absorption efficiency and in that case one wouldn't lose weight, because metabolically it's still absorbing the same amount of calories.

[spicyusername]

Interesting thought.

Do you have a source I can read through to understand more? I couldn't find anything supporting that idea.

Before dieting, I would expect most people to be in energy equilibrium, where their weight matches their calorie intake and calorie expenditure. Changing one side of that equation will change the equilibrium, every thing else equal.

If you eat more, you will gain weight. If you eat less... you will lose it. If you want to keep losing it, you have to keep eating less. Every target weight has an associated calorie intake / expenditure.

No doubt there are metabolic levers to pull to optimize the timeframe and that psychology and lifestyle play a big part of caloric intake, but, again, thinking about all that isn't really necessary.

Just eat less that you used to and be consistent about it. And if you're feeling spry, move more than you use to too. Keep tapering down until you're at your goal weight. This is the diet that is probably the best fit for 99% of people who are overweight. Dumb simple. No way to fail. Literally nothing to think about except the spoon, and maybe which route you're going to take walking around the block.