Yogurt may be substituted for meat in school lunches   WASHINGTON, DC - Under a new rule announced earlier this week by the U.S. Department of Agriculture, an 8-ounce cup of yogurt may now be substituted for the hot dogs, spaghetti and fish sandwiches. The USDA requires 2 ounces of meat or its equivalent in every school lunch. It already allows schools to substitute cheese, beans, eggs and peanut butter for meat. The idea of yogurt as a meat substitute in school lunches has created a stir among students across the country, many of whom have never even heard of yogurt.