Negative energy balance is the primary driver of body fat loss, and the magnitude of this energy deficit determines the extent of fat loss more than the type of exercise performed.

Study: Comparison of the Effects of Rapid, Moderate, and Slow Weight Loss Combined with a Low-Calorie Diet and Physical Activity on Inflammatory Factors in Obese Women

All the women lost weight by eating fewer calories and exercising, but those who cut calories slowly had better health results than those who cut a lot quickly. This suggests that how big the calorie deficit is matters more than what kind of exercise you do.

Study: Severe negative energy balance during 21 d at high altitude decreases fat‐free mass regardless of dietary protein intake: a randomized controlled trial

When people burn more calories than they eat, they lose fat—no matter what diet they follow or where they are. This study showed that even in a tough environment like high altitude, people lost the same amount of fat just because they ate less, not because of what they ate.

Study: Spot reduction: why exercise probably can’t help you target fatty areas of the body

You can't choose where you lose fat by doing specific exercises—like crunches for belly fat. The only way to lose fat is to burn more calories than you eat, and your body decides where to take fat from, not your workout.

Study: GDF8 and activin A blockade protects against GLP-1–induced muscle loss while enhancing fat loss in obese male mice and non-human primates

When people lose weight by eating less, their body sometimes loses muscle too — but this study found that blocking certain signals can help keep the muscle while making fat loss even better. This still means eating fewer calories is the main reason for losing fat.