ELI5: Explain Like I'm 5

Protein-sparing modified fast

A protein-sparing modified fast (PSMF) is a special diet that involves eating a lot of protein and very few calories overall. It's kind of like going on a super special eating plan where you only eat certain things to help you lose weight really quickly.

The goal of a PSMF is to help people who are really overweight or obese lose weight quickly while still getting the nutrients they need to stay healthy. When you go on a regular diet that's low in calories, your body will start burning both fat and muscle for energy. But when you do a PSMF, you eat enough protein to help your body keep your muscles while it burns fat instead.

When you eat, your body takes the food and turns it into energy that it uses to do all sorts of things - like running, playing, and even just breathing. One of the foods that gives your body energy is called protein, and it's found in things like meat, eggs, and dairy.

On a PSMF, you eat mostly lean proteins like chicken, fish, and turkey. You also eat some low-carb veggies like spinach, broccoli, and lettuce, but you don't eat any fruits or starchy veggies like potatoes or bananas. You might also eat some healthy fats like avocado or nuts, but only in small amounts.

When you're on a PSMF, you have to be really careful to not eat too little or too much. If you don't eat enough protein, your body will start to break down your muscles for energy instead of burning fat. But if you eat too much protein, your body will turn the excess into glucose (sugar) and use it for energy instead of burning fat.

Overall, a PSMF can help people lose weight quickly, but it's not a good idea for everyone. You should always talk to a doctor or registered dietitian before starting this or any other type of diet.