Best way to lose weight?

im looking for the best advice to lose weight, i have been over weight all my life (not an excuse) i eat healthy break 1 slice wholemeal toast lunch sometimes nothing dinner grilled or steamed everything healthy i eat a smaller portion then my 13 mth old son. i dont have any caffine or sugar or salt either. i walk min 40-50 mins a day as i have cervical spondylitis vigourous exercise hurts. i drink that cho yong tea 2 times a day and green tea or decaf tea/coffee. dont know what else to do. i dont sit much am alays busy with 4 kids. im 36 not getting any younger need help!!!!!! any suggestions please im desperate well must be to pay 35 quid for some bloody tea bags!!!!! ps tried slim fast, weight watchers and slimming world