Nutritionists say Americans don’t need more white potatoes. Congress disagrees – again. Lawmakers are encouraging the agriculture secretary to allow low-income pregnant and nursing mothers to buy white potatoes with the vouchers they receive as part of a government program. That goes against the advice of the Institute of Medicine, which advises the government on health issues. The institute has said recipients of such aid already eat enough white potatoes. It’s not that white potatoes themselves aren’t nutritious. But they’re often used to make french fries, which are usually fried or baked in unhealthy fats and oils. More