This answer is easy, and it's not what you'd probably expect. Most people on this site would say to not eat grains. I don't believe that at all, and I believe that the problems with grain are overstated. If you look at the history of this country, we ate MORE grain 100 years ago than we do now, yet diabetes and heart disease were comparatively rare back then. There is ONE change that mirrors the heart disease and cancer rate almost perfectly.
Soybean oil consumption.
My one bit of advice: avoid ALL PUFA seed/vegetable oils. Only cook with real butter, coconut oil, extra virgin olive oil, avocado oil, macadamia nut oil, non-hydrogenated lard or non-hydrogenated tallow (i.e. meat drippings).
My personal belief is that it's these oils that are making us fat. The oxidized PUFA content break down our cell membranes and make them permeable whereas a high saturated fat diet makes them firm and resistant. The newly permeable cell membranes are now far more susceptible to damage from lectins as they can much more easily penetrate the cells and damage DNA. So, the grain toxicity is exacerbated by the weakened cells from the oxidized PUFA, and this also allows the oxidized LDL to accumulate in our arteries, which wouldn't happen on a high saturated fat/low PUFA diet. While grain is not healthy, for the average person, they are not the #1 issue. It's the high PUFA diet that is not found anywhere in nature rearranging our genes and making them weak and susceptible to things that normally wouldn't be as damaging.
The beauty of this advice: it may be hard to give up cereal, pasta and bread for the average person, but I doubt you'll find a single person that'll miss canola oil. Seed oils are mostly flavorless with a light chemical aftertaste and have a disgusting texture. No one would miss them being pulled off the shelves.