I'm wondering if I drink 3 mugs of green tea a day instead of meals will I lose weight?

Skipping meals isn't. A healthy or effective way to lose weight. A study by maastricht university (holland) noted green tea has catechins ; caffeine w inhibition of o-methyl- transferase ; phosphodiesterase which effects thermogenesis ; fat oxidation. The linus pauling institute reported a study indicating that green tea can assist w glycemic control. Additionally, green tea has a diuretic effect.
Yes. Green tea has virtually no calories. However, skipping meals like that is not recommended.