Doug, it sounds to me as if, for you as for me, food is an intellectual
exercise as much as it is fuel.  It needs to engage you on many levels.
 Rather than the vague 'change your lifestyle', try doing something
specific.

Start by asking yourself the Three Big Questions:

Where am I now?
Where do I want to be?
How do I achieve that?

Start thinking of 'diet' as what you eat, whatever that is, rather than
the way you eat to shed weight or keep if off.  It may sound trite, but
it is quite difficult, and you have to pull yourself up and adjust your
internal vocabulary quite specifically many times a day.  You are never
'off your diet' for a start: this is just the way you ate today, and
tomorrow you will make a greater effort to make wiser choices...  If you
skipped a few fruit and veg portions in favour of chips and cake, make
those the changes to make this time, for this day.  If you find yourself
craving for something, look at why: what triggered it?  Time of day?  A
smell on the breeze?  A colour? A person?  And why is that a trigger for
that food craving?  For me the smell or freshly ironed clothes
(especially cotton!) remind me of cake and I want it...  The cats get
that smell when they lie up against the radiator, and a cat smelling of
cake...  Well!  ;)

Try a BIG change: rather than a specifically low calorie diet, take a
long and sensible look at a low GI diet.  Give it a few months.  If it
doesn't work, look at the options and try again.

Try planning: not just the main meals, but EVERYTHING you eat.  Once I
started doing this, I started losing those extra pounds that crept back
on...  It feels a bit obsessive at first, but it becomes like a Sudoku
puzzle: how can you fit X in this week?  What are you going to do about
Y?  I start by thinking 'I need to fit in 2 portions of oily fish for
health, one of red meat to keep the lads happy, and those 3 butternut
squash I bought but didn't use...  And those potatoes need using up
before they sprout into Dr Who monsters!' and I carry on like that,
adding in factors like friends for dinner, swimming evenings, the boy
going to scouts meetings, all that life stuff, until I have a week or
more of meals planned, and then I write the shopping list, marking the
stuff I need NOW and the stuff I need LATER.  Then I'm seriously sneaky
and send DH to get the shopping!  :D  THAT way I'm never tempted by
chocolate biscuits and Ben & Gerry's ice cream...  Once the meals are
planned, I forget about food until I need to cook it.  I check the menu
in the morning and fish out anything that needs to be defrosted, and set
aside time to relax and enjoy the cooking.  Learning to timetable
cooking time is important, especially if you love cooking, as I do.  It
doesn't have to take long: it's perfectly possible to have a 3 course
meal for six on the table within an hour.  If Nigella can do it, so can we!

I've recently made two whopping changes to my diet: it's taken a bit of
energy and thought, which is why I've been here a bit less than usual.
Now, I'm a BIG fan of WW and the way it works: for four years I counted
points, and I shed 70lbs slowly and carefully during the first three.
OK, there were health issues that slowed things down, but I got there.
I'd taken 20 years to put this excess weight on, so a couple or three to
get rid of it was no biggy.  So, it worked because I made it work for
me.  Then I hit goal, and discovered, as so many do, that maintaining is
NOT as easy as it seems!  Slowly, over the year, half a stone slid back
on, and my joints were feeling it.  So a month ago I switched to the
Core program.  I stopped thinking about five portions of fruit and veg
per day as what I *ought* to have, and started thinking of it as an
absolute minimum.  I now aim for 10!  I stopped the snack bars and the
nice biscuits, and only had my social cake at the meeting each week.  In
the month I've shed three pounds: I put a measly half back on the week
of my son's birthday sleepover, but on the whole it was a good month.

Then came the second HUGE change...  I've stopped eating wheat!  This is
MUCH harder than going on a fat free diet because you can no longer
process fats after your gall bladder is removed!  You end up reading a
whole lot of seriously BORING stuff on the backs of packets, looking for
wheat based products like malt extract, for a start.  And beer...  I
might have to give up beer too.  :(  I need to ask about that.  Not that
I drink much anyway these days, but a decent pint of beer is a singular
joy...

This change was brought about by a long and serious discussion with a
coeliac friend and some research into alleviating rheumatoid complaints
through diet: my fibro has been seriously unpleasant this year, and was
topped off by spending 3 hours in A&E thinking I had a broken thumb
joint.  It was a huge relief to find that it was 'only' an acute and
very localized flare-up of the fibro.  Cutting out all wheat products
COMPLETELY seemed to be a key factor in reducing joint issues, so I
decided to try it.  I'm giving it six months, but it has to be a
complete cut out.  NO occasional slices of cake unless it's wheat free:
wheat free bread if I MUST have toast (though bread is not a Core food,
so I've cut it down considerably anyway).  It's a seriously good thing
that I DO love cooking, have always cooked a huge amount of our food
from raw ingredients, and like the intellectual challenge, because it
goes very much against the grain (ooer!  Sorry!) to be fussy, and it's
bad enough with the fats issue!

So give it a good hard think: look at the things that are possible for
you, and think 'How to I do that?' rather than 'This is so difficult'.
Make a big change, and make it work: no compromises because it's hard.
Look at the challenge and work out how to succeed rather than how to
bash the change to fit the old regime.

Bread is a BIG issue for me.  I do LOVE bread in it's many wheat based
forms, but it has to go...  So rather than look at all those gluten
removed flours with added gums to replace it, and anaemic loaves that
refuse to turn into toast, I'm looking at alternatives such as rye and
barley flours, and finding out why wheat has taken such a hold on the
western psyche.  And I'm finding out where and how different breads were
developed, and the subtle but profound differences between noodles and
pasta...

So go and look at something like a low GI diet, and rather than
rejecting it as too difficult, decide how best to make it work for you.
 Look at the traditional Japanese diet as well. What kept them so slim
and healthy for so long?  WAS it simply diet?  How did lifestyle impact
on it?  And why are so many more folk getting so much fatter now?  It is
all to do with diet, or are we less fit because we do less physical
work?  ARE we less physical than our ancestors?

And good luck!  You are going to need it.  BUT you are a bright and
intelligent man who CAN do this.  If and when you need help, moral
support, a good argument, someone to whine at, someone to toss them back
 when you throw the toys out of the pram, we're here: that's what this
is all about.

the diet/lifestyle argument is one of perspective and how you look at what
your are doing... HTH, Lee