In rats, not getting enough zinc lowers their metabolism and changes how they burn fuel, but this happens mainly because they eat less, not because zinc is directly messing with their energy systems. The drop in energy use is basically just a side effect of them being less hungry.

When adult rats don't get enough zinc in their diet, their bodies burn energy at a slower rate, even if they're eating less just because they're being fed the same amount as a control group. This suggests that low zinc levels directly tell the body to slow down its metabolism.

When mice are fed a diet with almost no zinc, they eat and drink significantly less, especially during the day. This lack of zinc might mess with their hunger signals, making them feel full faster and causing them to lose weight.

When rats are put on a restricted diet, they usually become much more active, but this only happens if they have enough zinc in their system. If they lack zinc, their activity levels stay normal instead of spiking, showing that zinc plays a key role in how animals move when they're hungry.

When mice don't get enough zinc in their food, they lose muscle and overall weight instead of fat. This shows that zinc is really important for keeping muscle strong and building new tissue.

Feeding mice a diet with almost no zinc for six weeks makes them eat less and move less, but their overall calorie balance stays the same. This means any weight they lose comes from changes in their body's tissues, not from burning more calories than they eat.