How It Works: Fast for 14 (women) to 16 (men) hours each day, and then “feed” for the remaining eight to 10 hours. During the fasting period, you consume no calories. However, black coffee, calorie-free sweeteners, diet soda and sugar-free gum are permitted. (A splash of milk in your coffee won’t hurt, either.) Most practitioners will find it easiest to fast through the night and into the morning. They usually break the fast roughly six hours after waking up. This schedule is adaptable to any person’s lifestyle, but maintaining a consistent feeding window time is important. Otherwise, hormones in the body can get thrown out of whack and make sticking to the program harder, Berkhan says.
Not only that, but growth hormone is increased during fasted states (both during sleep and after a period of fasting). Combine this increased growth hormone secretion:, the decrease in insulin production (and thus increase in insulin sensitivity ), and you’re essentially priming your body for muscle growth and fat loss with intermittent fasting.
For this plan, eat clean for five days of the week (you can pick whatever days you want). On the other two days, restrict your calories to no more than 700 each day. Calorie restriction unlocks a lot of the same benefits as fasting for an entire day. On your non-fasting days, you’ll need to make sure you're getting in healthy fats, clean meats, vegetables, and some fruits, and you can structure your meals however best works for you. On restricted days you can have smaller meals or snacks throughout the day or have a moderate-size lunch and dinner and fast in the morning and after dinner. Again, focus on healthy fats, clean meats, and produce. An app like MyFitnessPal can help you log your food and keep track of your calorie intake so you don’t go over 700.
In one study, protein and carbohydrates were more efficiently absorbed in individuals who completed a cardio workout after fasting, as opposed to those who consumed a carbohydrate rich breakfast prior to working out. This research indicates that fasting can assist your body to more efficiently absorb nutrients from your post-exercise meals, as well as improve your general health and boost lean muscle mass growth.
One thing to consider about bone broth that sets it apart from plant foods: Even if you do eat a variety of plants that contain collagen-boosting nutrients, if you have a weakened digestive system, you may not fully absorb them. On the other hand, the collagen in bone broth is incredibly easy to absorb, even for those with compromised digestive systems.
When you eat a meal, your body spends a few hours processing that food, burning what it can from what you just consumed. Because it has all of this readily-available, easy to burn energy (thanks to the food you ate), your body will choose to use that as energy rather than the fat you have stored. This is especially true if you just consumed carbohydrates/sugar, as your body prefers to burn sugar as energy before any other source.