To boost all your Sim's stats by 3 temporarily, create a meal using Egg, Milk, Whole White Flour, and Corn Oil. Put it in a food processor, then in an oven. The meal will have sparkles coming out of it. When you eat it, all your stats will be boosted by 3 temporarily. Alternately, create a meal using Chicken, Onion, Egg, and Milk or Carrot, Egg, Milk, and Whole White Flour.
