Those studies above, in working with small sample sizes, and different types of fasting than recommended here, would lead me to believe that fasting affects men and women differently, and that many of the weight loss benefits associated with intermittent fasting (that affect insulin and glucose responses) work positively for men and negatively for women.
Is intermittent fasting safe? Remember that you’re only supposed to fast for twelve to sixteen hours and not for days at a time. You’ve still got plenty of time to enjoy a satisfying and healthy diet. Of course, some older women may need to eat frequently because of metabolic disorders or the instructions on prescriptions. In that case, you should discuss your eating habits with your medical provider before making any changes.

So how long does it take to go into ketosis when fasting? On a standard keto diet, it typically takes around 2–3 days to reach ketosis, although it can take up to seven days in some cases. However, many people find that keto adaptation intermittent fasting can speed up the process and help your body burn through glycogen stores more quickly to help enter ketosis.
Reheating coffee breaks down the components, resulting in a bitter taste. With no cream or sugar to balance the flavoring, black coffee will more immediately taste bitter when reheated. If you find you must reheat your black coffee, absolutely do not use the microwave. Reheating coffee this way will break down the aromas and cause your coffee to taste stale instantly.
How It Works: Warriors-in-training can expect to fast for about 20 hours every day and eat one large meal every night. What you eat and when you eat it within that large meal is also key to this method. The philosophy here is based on feeding the body the nutrients it needs in sync with circadian rhythms and that our species are “nocturnal eaters, inherently programmed for night eating.”

Even though this plan is advanced, it's very simple. Don't eat anything every other day. This is the most intense form of fasting but can produce amazing results. Every other day, eat healthy fats, clean meat sources, vegetables, and some fruit, and then on your fasting days, you can consume water, herbal tea, and moderate amounts of black coffee or tea.
There were [no statistical] differences between the low- and high- [meal frequency] groups for adiposity indices, appetite measurements or gut peptides (peptide YY and ghrelin) either before or after the intervention. We conclude that increasing meal frequency does not promote greater body weight loss under the conditions described in the present study.