If you drink a protein shake outside of your eating window, it will break your fast.
A protein shake is a caloric beverage, and if you eat or drink anything containing calories, you are, by definition, no longer fasting. So, save it for your eating window!
🥤 Protein shakes during your eating window
If you’re on intermittent fasting, you should look at your protein shake like you would at any other food or beverage — save it for your eating window. But during that window consume it however you typically would!
If you’re fasting for weight loss, protein is vital. Your body digests protein more slowly than carbs, that’s why protein can help you feel satiated longer. And protein changes the levels of hormones that control your appetite. Protein reduces your production of ghrelin — the hormone which tells your brain you’re hungry. It also increases the levels of hormones that tell your mind you’re full.
This hormonal release means if you consume more protein, it can naturally help you eat less without feeling hungry. But don’t overdo it. Your body will break excess protein into sugars through a process called gluconeogenesis, which causes your body to release insulin and signals it to store fat, defeating your weight loss effort.
Do you need a protein shake?
Protein shakes are convenient but may not be the best way to add this macronutrient to your meals. Most protein shakes are packed with artificial sweeteners, are high in calories and low in other nutrients, and they often contain a low-quality “whey isolate.” If you’re fasting for better health, then you may want to add high-protein foods to your eating plan instead.
Good sources of protein include most animal products (including milk and eggs), legumes, tofu, and nut butter. Beans and whole grain rice together form a complete protein as well.
There’s no reason you can’t enjoy a protein shake while you’re intermittent fasting. Be sure to drink it during your standard eating window and try not to think of your protein shake as a beverage. Like any other caloric beverage, a protein shake will break your fast and might undo your efforts.