step one is to start educating yourself on the various diet philosophies out there...
atkins, bad fat of any kind is better than carbs of any kind
south beach, atkins, with a focus on healthier fats
glycemic approaches, similar to above, more stats
french diet, eat anything, strict portion control
mediterannean, "natural" unprocessed foods out of the field, out of the sea (not so much the inauthentic American Italian focus on pasta)
slow food, dinner should take an hour to make and an hour to eat
pre-loading, bulk up with fibre before meals
as a general comment, the current thinking is that sugar (actual sugar, breads, pasta) converts to body fat easier than actual fat, which is counter intuitive.
Its like throwing gasoline on a fire vs hardwood. Gasoline creates a big flare then is gone, and you need more, whereas hardwood will sit there and burn for 3 hours.
So, fat is hard to digest...it has to be converted to sugar to be absorbed by the body, and in a way, this inefficiency works in your favour...the key is hunger abatement per calorie consumed.
The idea is improved by south beach, which says this is true, but you may as well eat healthy fats, like olive oil or canola or fish, and double the benefit, and if you eat carbs, whole grain carbs in moderation are ok.
my DW could probably write a book...she calls it the not-eating diet. If her weight gets above target, she just stays on tea till dinner, then maybe just has a salad. As a general rule, she tries to delay first meal as long as possible...I think this is to stay in fast as long as possible during the day....at night, we all slip into fast, which is the body digesting its own fat...once you eat in the morning, the body switches to craving food.
one consideration is that in olden days, when work and liesure was very physical, we could consume 5000 calories and not gain weight. For those with sedentary lifestyles, the non-weight gaining caloric load might be closer to 2000 calories, however, this gives your body less than half the chance to grab the trace nutrients its needs, and given that even vegetables do not have the minerals and stuff that they used to have given the depletion of soil and how its grown, in the modern age we are starving our bodies of nutrients more and more....so I suggest supplementation.
weight loss is one thing, but longevity is another. All the science points to eating like cavemen, focusing on an uncooked plant-based diet, with meat, if any, used as more of a condiment, and to keep your B12 from dropping off. Vietnamese diet is very close to this.
sorry if I am repeating stuff already covered...I am new to this part of the forum.