An example of an minimalist approach to raw feeding is the Meat with Bone diet advocated by Michelle T. Bernard. Critiques of raw diets include the concern with the possible nutrient imbalances that can arise feeding any type of raw diet. Raw-meat based diets (RMBDs) are composed of uncooked ingredients derived from animal species that are fed to dogs in home environments. Ingredients can include a variety of animal parts including muscles, organs and bones. RMBDs can be designed commercially or home-prepared by the owner. Commercial RMBDs are typically formulated to meet AAFCO nutrient requirements although some products are designed for supplementation and are not nutritionally balanced. The BARF diet was originally defined as Bones And Raw Food diets but has since been changed to Biologically Appropriate Raw Food. The original BARF diet was popularized by Dr. Ian Billinghurst, advocating feeding 60% raw, meaty bones. The rest of the diet is to be composed of a wide variety of foods including vegetables, grains and legumes. The "prey model" diet attempts to create a diet that simulates the proportions of ingredients and nutrients seen in a prey animal's diet. In the wild, a predator gains nutrients not only from the meat and organs of the prey they are eating. A wild animal would also gain nutrients from the food their prey has previously consumed. This diet aims to simulate all the nutrients that the wild animal would obtain. Actual whole prey are used whenever possible, including whole rabbits, chickens, game hens and turkeys. Generally, the diet recommends 80% meat (including some 'meaty' organs such as heart), 10% bone and 10% organs (of which half is liver). Proponents of the whole prey model diet believe dogs and cats are natural carnivores and do not have any nutritional needs besides what is found in meat, bones, and organs. The supporters of the prey model also focus on feeding meats from a wide variety of animals. Some also add small amounts of vegetable matter to simulate the consumption of stomach contents of prey animals. Supplements are generally not used in a prey model diet although some followers do add fish oil to the diet to compensate for the reduced amount of omega-3 fatty acid in commercially raised grain-fed livestock. This problem can be partially mitigated by using grass-fed meat, which has more than double the omega-3 content as grain-fed meat. At home preparation of raw food diets entails the use of wholesome ingredients that can be easily accessed by the owner.