Agree. actually during NS still quite ok. but once you left NS
for your civilian life, it will definitely shootup. my is a typical
case. Luckily, last year, manage to slim down around 20kg (from
pre-NS 85kg to post-BMT 76kg to 1 yr after ORD 96kg to around 76kg
in half a yr)
Advice for those going into obes coy:
i) Dun take all the 5-6 dishes available for every meal (3 is
enough)
ii) take lesser meat and rice (or noodle), and more veg and soya
product.
iii) Control your diet (dun over eat) when you are 1st release from
the 'cage'.
iv) Make sure you lose some weight every week, or else can say
bye-bye to that very weekend release.
v) Set a goal what is your ideal weight after that 4mths of
training, and work towards that goal.
For eg. now weighs 86kg. ideal weight is 70kg. 16kg to loss.
during that 4 mths, just have to make sure every week lose 1 kg.
Hence by end of the 4mths (4x4=16 weeks later), you will find young
and old girls magnetised to you by your charm. 
vi) Last of all, HAVE FUN!