Your body needs certain nutrients to meet the demands of the moment. You don’t need a heavy meal if you’ve been sitting around all day using very little energy, but you probably need a good amount of protein if you’re recovering from a hard workout. While carbohydrates can be stored as glucose for energy or fat, too much protein that your body doesn’t need gets stored as fat, especially if you’re not very active. Your source of protein could also affect your cholesterol levels. In particular, most animal protein sources will also have a significant amount of artery-clogging fat (per the Mayo Clinic).
Per the National Kidney Foundation, your kidneys work to remove excess protein and filter out waste from your body, and you’ll make them work overtime if you pile on more protein during a single meal. The waste from processing protein can build up; this could mean more trips to the bathroom as your kidneys rid your body of waste.
Although your body can absorb a lot of protein at once, a 2018 study in the International Society of Sports Nutrition said that eating too much at once can affect the absorption of fewer concentrated amino acids in the body. The study suggested mixing different types of protein sources, such as fast-digesting whey with slower-digesting casein so that you can maximize the absorption of the nutrients you need.