We've been following the Tinsley House diet / supplements / exercises for 7 weeks now and so far, have had really good results. There are two books - Is That My Child? and The Brain Food Plan which goes into more detail on the diet and has a two week eating plan.
We ate quite well before but have upped our fish intake considerably, now have cooked breakfasts and cut down on carbs. Apparently craving carbs/ salt / sweet stuff is part of the problem for our children along with faddy / fussy eating. I thought ours would howl at the changes, but they have been incredible. I found it very daunting to start with, but after a few weeks it became second nature and I'm much more organised than I was 
As Plenty says, we get them involved in the cooking and they have aprons, chefs hats etc. We've also given everything good names - the book talks about Rat Stew (ratatoulle) and we also have Oaty Oats, Yummy Chook toast (chicken pate) and Seedy Slice etc. I hide veg in everything - today we had lasagne with tons of grated carrots and leeks in the meat sauce and blitzed spinach in the cheese sauce (Popeye Sauce).
Most successful of all is Dinner Winner for whoever finishes anything first. We've made up a silly chant and they love it. Everyone who finishes is a dinner winner, but there is always a first place / gold medal. No treat, just glory and to chose their plates /cup colours at the next meal.
DS has always had terrible wind and reading lots about this on the Special Needs board I think he's probably reacting to either gluten or milk which is a pain. I'm going to ask the doc for a gluten blood test and see how we are getting on after a couple more months.
Happy to waffle on more if it helps
Good luck!