true enough...muscle weighs more than fat, so weight alone doesn't tell you much.
if you know your body fat percentage, however, you can use it with weight to see how much fat you're losing, and the lean mass gained.
Diet is the #1 area where people fail when they try to get into better shape. Just about any exercise is sufficient...but for americans, our diet sucks, and too much misinformation screws people up and leaves em confused and starving.
Only a tiny minority of people with actual metabolic issues would need super low calories to lose weight...and usually they get thyroid therapy to increase metabolism to a more normal level.
best way to ramp up metabolism naturally (and assuming normal metabolism) is to eat smaller meals, more often. its like keeping a fire burning...not enough wood, and the fire tries to burn out, and isn't very hot. too much wood, and the fire smothers due to lack of oxygen...and again, doesn't burn as hot.
But toss a couple smaller logs on every hour, and that's gonna be one raging bonfire!
The human body isn't much different. We evolved as hunter/gatherers, eating what bits of food were available throughout the day. 3 square meals came about during the industrial revolution, when more people began to work in factories, than at home on the farm (when they could take short breaks for a bite..not a single lunch hour 4 hours into the shift).
We have yet to evolve to the point of being able to take in just 3 meals a day and use it efficiently. And if you think about it, many people do have snacks in the afternoon, or late evening after dinner. turn those snacks into healthy things, and its a step on the right path to success.