None of the coffee additives caused a significant drop in our blood ketone levels. At 120 minutes, my, (Becky’s), ketone readings increased after drinking black coffee, coffee with cream, coffee with MCT oil, and coffee with butter. At 120 minutes, Keith’s ketone readings dropped by 0.1 mmol/L after drinking only black coffee. His ketone readings rose slightly after consuming coffee with cream, MCT oil, and butter.
For example, in the graphic below you would eat dinner on Monday night and then not eat again until Tuesday evening. On Wednesday, however, you would eat all day and then start the 24–hour fasting cycle again after dinner on Wednesday evening. This allows you to get long fast periods on a consistent basis while also eating at least one meal every day of the week.
Since all of your hormones are so deeply interconnected, when one hormone is thrown off balance, the rest are also negatively impacted. It’s like a domino effect. As the “messengers” that regulate nearly every function in your body — from energy production to digestion, metabolism, and blood pressure — you don’t want to disrupt their natural rhythm.

Fat loss. Keto and intermittent fasting are a one-two punch for losing weight. Fasting and keto both spontaneously increase fat loss, even when people don’t intentionally restrict their calories.[18][19] When you pair intermittent fasting and keto together, you become a fat-burning machine. The weight comes off quickly, and because keto also suppresses ghrelin, you don’t get nearly as much of the hunger and feelings of deprivation that usually accompany weight loss.
While the idea of fasting can be overwhelming, especially if you haven’t done it before, intermittent fasting can actually be a lot easier than many other types of eating plans. Since you are fasting for time restricted chunks of the day, you’ll be eating less food, which eliminates a lot of the stress around having to meal prep. During the periods of time in which you're eating, you’ll still want to focus mainly on healthy fats, clean protein, and carbohydrates from whole food sources—but this isn’t an excuse to hit the drive-thru and load up on sugar the rest of the time! Here are some of the effects of intermittent fasting:
This is the same as the 8-to-6 window plan, but you are extending your fasting time an extra four hours. I personally practice this plan during the workweek. I'm not a breakfast person, so I just enjoy a few cups of herbal tea to start my day. With this plan you will be eating only between the hours of 12 p.m. and 6 p.m. for a full 18 hours of fasting within a 24-hour period.
Put a coffee filter or your cheesecloth (you can even use a paper towel if you don’t have a coffee filter/cheesecloth) into the mesh strainer and place it over another glass container. Gently pour the filtered coffee through the filter and let it slowly drip into the glass container below. If the filter fills up, just wait and let it drip naturally (this could take up to 10 minutes).

While it’s not technically fasting, some doctors have reported intermittent fasting benefits by allowing such easy-to-digest food as whole fruit during the fasting window. Modifications like these can still give your digestive and metabolic system a needed rest. For example, “Fit for Life” was a popular weight loss book that suggested eating only fruit after supper and before lunch.
Stable blood sugar levels are vital to the success of any diet. This is because when glucose levels plummet, it leads to intense hunger, which almost always results in binge eating. Stable blood sugar levels help eliminate headaches, lack of focus, poor memory, and brain fog as well. Interestingly, these are common complaints among those who follow high carbohydrate diets, as opposed to diets that are rich in fat and protein.
Although there's no specific dietary recommendation when intermittent fasting, many people choose to combine it with a low-carb, ketogenic diet. When it's time to eat, include foods that are high in good fats and low in carbohydrates. That means eating nuts, seeds, vegetables, avocado, olives, meat and fish, while avoiding whole grains, fruits, starchy vegetables, sugary drinks and anything processed.

Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though people struggled with the fasting days. So I had written off IF as no better or worse than simply eating less, only far more uncomfortable. My advice was to just stick with the sensible, plant-based, Mediterranean-style diet.
Not only that, but growth hormone is increased during fasted states (both during sleep [5]and after a period of fasting). Combine this  increased growth hormone secretion:[6], the decrease in insulin production (and thus increase in insulin sensitivity [7]), and you’re essentially priming your body for muscle growth and fat loss with intermittent fasting.