Help me lose weight please fitness guru types.

[Stan_Lite]

I weighed myself a few weeks ago and, to my horror, I was 17st 2lbs - the heaviest I've ever been. I've been a fat chap for several years now but it hasn't really bothered me until now.

I started off at home by eating better food (and less of it) and doing a bit of walking and it seemed to be working fine. I lost a stone in 3 weeks. Then I went on holiday for a week with my brother and put 4lbs back on due to drinking beer and doing sod all. I wasn't bothered about that as I expected it. I got back and the following day I had to head off out to work (for those who don't know, I work 4 weeks on, 4 weeks off on an oil rig in Egypt). I got to the rig on Sunday and I had dropped 2 of the pounds I'd gained on holiday, so all was well.

I decided it was time to get serious about it so I started watching what I eat and decided to use the limited facilities in the gym on the rig. I started using the treadmill and got a bit of a buzz out of it.

Now we get to the bit where I need advice. I started off doing 1 hour sessions at approx 70-75% (145-150bpm) of my max heart rate (180bpm). I've done this for 3 nights now and when I stood on the scales this morning ... lo and behold, I'd GAINED 3lbs in 3 days
I've done a bit of looking around on teh interweb and read somewhere that if you start exercising hard after a long spell of no exercise (sounds about right) your muscles can sometimes store fluid to help repair themselves or it may just be natural water retention which will go away on it's own. If anybody has any ideas, I'd appreciate some advice.

I think I've probably started off too enthusiastically and have been thinking I'll have a break tonight and then cut down to 1/2 hour sessions to start with and build up a bit more slowly. What do you guys think?

A few details to help you:

Age - 43 years.
Height - 5'10" = 1.78m
Current weight - 229lbs = 16st 5lbs = 104kgs
Cigarettes - 20 a day

Typical day's eating on the rig
Breakfast (05:30) - bowl of bran flakes with milk (only full fat milk on the rig unfortunately), 1 glass of apple juice and 1 cup black coffee.
Tea break (09:00) - 1 small slice sponge cake and 1 cup black coffee.
Lunch (12:00) - 2 small (or one medium) chicken portion, 1 medium baked spud, salad and a piece of fruit.
Afternoon break (15:00) - 1 piece fruit.
Dinner (18:00) - 1 bowl soup, chunk of bread and more fruit.
After workout (21:00) - 2 pieces fruit.
I normally drink about 2-3 litres of water throughout the day.

If anybody can give me a few pointers, I'd be most grateful.

Also, can anyone recommend me a good heart rate monitor - I don't trust the one on the treadmill on the rig - it seems to jump around a lot. It seems to mainly stay around the level I want it to but occasionally drops down to 110bpm and then jumps up to 212bpm randomly. I'd like to have a monitor I can trust to read accurately.

Thanks in advance for any advice