Situps and crunches dont burn fat off yoru abs!
they strenghten yoru stomach muscles, running burns fat,
Aerobic exercise burns fat! But you have to do 20 mins of it minimum to start the fat burn cycle, Aerobic exercise first thing in the morning before you eat will burn twice as much fat as if you have already eaten!
as your body takes energy from the food in yoru stomach as well as the fat stored!
If there is no food it purely burns stored KJouls, But it doesnt start burning until you have got yoru heart rate up to aerobic status wich takes 20 minutes to initialise!

Try it over 2 weeks, if you work in 4 min incriments, 3 mins of skipping, then 1 minute of pushups/situps/stretches then back to skipping for 3 min rounds! and so on for say 5 times in total!
if you did this morning and evening and then ate rice and veges a bit of meat and seafood, but mainly rice but in small portions you will lose 5 kgs a week! I guarentee it! Maybe not in the first week but you will boost yoru metabalism and keep it up youll feel more active and the fat will drop off and your exercise wont seem like a chore but rather youll want to run everywhere!
but you have to push yoruself to do it!
Take the stairs and not the lift! little things like that make a difference!
Dont eat big meals before going to bed as the food just sits in yrou stomach and turns to fat!
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True words spoken from an ex fat bastard, who has dropped 20 kgs!