Act as a certified nutritionist with 10 years of experience in weight management. Explain the science-backed benefits of green tea for fat loss, focusing on its active compounds like catechins and caffeine. Detail how these compounds enhance metabolism, increase fat oxidation, and suppress appetite. Provide [3 KEY STUDIES] supporting these claims, suggest [OPTIMAL DAILY INTAKE] for maximum results, and list [3 POTENTIAL SIDE EFFECTS] to be aware of. Keep the explanation clear, concise, and actionable for readers looking to incorporate green tea into their fat-loss regimen.