A 2024 dose-response meta-analysis of 116 RCTs (6,880 participants) found steady-state aerobic exercise reduced body weight, waist circumference, and body fat percentage in a linear, dose-dependent way up to 300 minutes/week, with 150 minutes/week at moderate intensity (in Zone 2's range) producing clinically meaningful reductions in waist circumference and body fat.
Interval training reduced body fat about as much as steady cardio in 13 studies, in about 40% less training time, without much change in body weight.
People lose about 3 kg compared with eating freely, but no more than with ordinary calorie cutting: the loss comes from eating less.
In overweight adults, sprint intervals reduced body fat percentage by a moderate amount, similar to regular HIIT.
In a tightly controlled two-week trial, people ate about 500 fewer calories a day on unprocessed food than on ultra-processed food and lost 0.9 kg instead of gaining it.
Walking programmes in inactive adults led to small reductions in body weight, BMI and body fat across 37 trials.
In a controlled crossover trial, curtailing sleep during a calorie-restricted diet shifted weight loss away from fat and towards lean mass, and increased hunger, compared with adequate sleep.
Small help with weight by keeping you fuller.
In trials of adults on a weight-loss diet, those told to drink extra water (often 500 ml before meals) lost 44–100% more weight than those who were not.
Small help with body fat during dieting, mainly by keeping you full and protecting muscle.
