The golden rules
The main rules: moderation, especially when it comes to fatty foods, quick-release sugars and anything in large quantities; satisfaction, which you can achieve by drinking more, eating more fiber (fruit and vegetables), slow-release sugars (bread, pasta, rice and cereals, especially wholemeal) and water, by having sensible meals and sensible snacks, and by varying what you eat, which will help your body get back to normal after you've abused it by smoking (fruit and vegetables for vitamins and minerals, meat and lean fish for protein, dairy products for calcium).
A typical day
The basics: 2 - 5 piecces of fruit, 1 portion of cooked veg and 2 portions of raw veg, 1 - 2 portions cooked carbs + a piece of bread with each meal, 3 dairy products, 1 portion of meat or fish, and a little vegetable fat.
Star by having a good breakfast (drink, dairy product, piece of fruit, 2 pieces of lightly-buttered wholemeal bread) and take your time to enjoy and digest it. At 11 o'clock, have a piece of fruit and a yogurt if you're hungry. At lunchtime, go for fish, carbs and veg with no sauce and then fruit and a yogurt. Snack on fruit. Have a light evening meal: grilled meat or fish, green veg, fruit or mixed salad, a yogurt and a piece of fruit.
How to keep going
At the beginning, when you sit down to eat, especially if you're out, stay well away from smokers - they'll understand. At the end of your meal, develop a routine to stop you craving a cigarette: suck a mint or go and brush your teeth for example. Before dinner, if you're used to having a glass of wine and a cigarette, change your routine and have a relaxing bath before you eat instead.