Any wheat and any potatoes according to people like Gary Taubes. Sweet potatoes are probably better than regular spuds. Wheat and potatoes are mostly just carbohydrates which, as explained in the video we're discussing, should be reduced. There's no such thing as an 'essential carbohydrate' and all other vitamins and minerals in potatoes and wheat can also be found in more than sufficient quantities in 'good' foods like meat and leafy veggies.