It depends on the question you are asking. Our lab studies the effects of maternal high fat diet on DOHaD in offspring. Others use a Western diet (high fat and carbohydrates). There is the Agouti mouse model (from Duke) and a leptin knock out mouse (ob/ob) that is obese and develops Type 2 diabetes. Many things to consider in your study design - See Rebecca Simmons Review including PMID: 21110912 and others.