hey im same age as u and i am severely overweight during my sec
sch days. sec 1 when the P.E. teacher took my weight, he shook his
head as i am 88 kilos at a 170 height. i still remember the look on
his face till now. however, during the end of sec 1, i picked up
basketball and became really active with a group of friends altho i
did not join the sch team. we played like 3 times everyday and i
would clock up half a day during the wkends.
i cant seem to diet as i love food. i eat the usual stuff that
my parents cook with one full plate of rice. if ive not picked up
basketball i would have exceeded 100kilos by sec 2. i have low
metabolic rate too as it is evident that i put on weight really
easily, however, i felt my body getting more active and i dont feel
tired easily after i began excercising.
now when sec 2 start, my sch TAF club made me jog 1.5 km
everymorning, and some part of the route goes uphill somemore.
thats really hard for me to take and i feel my whole body aching
up. however, after a few months, i can do that distance without
even gasping for breath, and it makes me feel damn good whenever i
broke out the sweat. im not tired during lessons too!
i started slimming down significantly, not to the 'skinny' state
but to the 'fit' state. at the end of sec 3, i weigh a mere 74 kg.
and i did not even try to diet! im quite sure ur low metabolic rate
is due to your dieting, id say eat a hearty mael but then excercise
regularly.
now when im in poly, it got harder for me as ive picked up
smoking and then ive quit the 1.5 km every morning. -_- from the
first year of poly till now that i started working, i only play
basketball once every weekend for 3-4 hours, id usually go clubbing
during the other weekend (dancing is great cardio too) well sadly,
ive my weight now borders between 79-80 but ive built up my muscles
and hv a nice body frame. (i wear 'm' size for clothes frm topman,
have to wear 's' from timberland of fat face).
so my point is, excersice really does wonders. dont think of
excersizing as a way to lose weight, rather, pick up a cardio
intensive sport that you like and then clock in serious hours
every week working out. make it a habit! and i tell you that your
metabolic rate is definately gona improve and you will become more
active when you start excersicing regularly, matter fact, i havent
even try the other methods of losing weight (wanted to, but never
bothered to find out more) like acupuncture and pills.
oh and one more thing, im also very anti-social when i was fat.
but now id like to blive tht im a confident young man, i can chat
with the opposite sex rather easily and im comfortable on the dance
floor with the girls. so hopefully i can be a motivation to you. i
realise tht the 'bigger' girls who've lost weight are definately
more sexy then those skinny and scrawly girls 
so get out of you house now and make use
of the good weather today babe! 
sry to everyone
for the long post