Is intermittent fasting safe asked by a blog reader

By Vince

I had a really good and relevant question from Ben Miller. He asked whether intermittent fasting was safe? See the article. This is a really good question because it has a great deal of depth to it. Here's a more complete answer.

Intermittent fasting is safe if you are well nourished and above your minimum amount of fat (around 5% for men and 10% for women).

I would be more selective with fasting by swapping the high sugar, pure starch and pure oil items from your diet a little at a time. This is because these components of food offer the least nutrition. Replace with fibrous carbs (leafy green vegetables), beans, seafood, fruit, meat and whole grains. (Have some organ meat like half an ounce of organic liver, an egg and cod liver oil everyday - to make up for vitamins D, B12 and omega 3 fatty acids.). These new foods will provide you with the minerals, vitamins, essential fatty acids and proteins you need on a fast but not the calories. (In addition you will want to ensure you are getting some vitamin K2 with some natto or grass fed derived hard cheese or butter).

If you do not have all the nutrients that you need you can not function properly.

Intermittent fasting is broadly calorie restriction because you can't eat as much in a shorter period (an eating window as fasting people call it) but you do need to overcome the sensation of hunger until you make it a habit. So initially it is very difficult to do. (Intermittent fasting can also be called meal skipping if you don't like the fancy name).

If you can do the above substitutions (replacing low quality foods for high quality ones) you will put more nutrients into your body. By being more discerning with foods that offer many micronutrients and small amounts of essential amino acids and essential fatty acids - non of which the body can make - you reduce calories without reducing micronutrients.

I would suggest you build up the hours on a fast to test whether it suits you or not. So if you have your last meal 2 hours before bed, try to have that meal 3 hours before. Then 4 hours. If you can manage that then try 5 hours (at the 5 hour mark the last meal merges with another meal time so you eat less because you have lost 1 meal time). It has to be manageable otherwise don't do it. (The 2 reasons why I picked before sleep is firstly it is easy to remember and secondly; because your growth hormone reaches a peak within the first 2-3 hours of sleep. If you are still producing a lot of insulin due to eating before bed it blunts the growth hormone release.)

Intermittent fasting is quite a natural practice for humans in the past when food was less reliable than it is today. We have fat stores so that we can go without eating for long periods of time. Consider this, as an extreme example, if a person has about 30% fat by body weight and they weigh 160lbs. That person has 48lbs of fat which is roughly 168000 Calories. That is a lot of fuel and if you burned 3000C a day that is 56 days of fuel! (Now, that is in theory but when we get to essential body fat which is about 5% in men and 10% in women - it becomes very difficult to lose anymore fat. Any more loss in fat would adversely affect your health - you need a little fat to cushion your organs, your heart needs a little fat around it for emergency energy supply, there is fat in your eye sockets to cushion impact, your lean body tissue breaks down (your body prioritises fat as much more important when you get to very low levels) etc. So the 56 days, for the above example is not entirely accurate because you tend to settle at minimum body fat which can be dangerous. You will also have depleted many of your micronutrient supplies long before 56 days if you ate nothing. However if you got all the essentials but not sufficient calories then you could last much longer and continue to lose fat.

Lets put calories aside for a moment, a micro nutrient like vitamin C is extremely valuable and a prolonged deficiency can kill you faster than a lack of calories can. You probably have heard about scurvy before where the body falls apart because without vitamin C, collagen formation is unstable. (Roughly speaking collagen is like a glue that holds the body tissues together.)

So when you fast you don't want to remove micronutrients (all the vitamins, minerals) and you don't want to get rid of essential amino acids and essential fatty acids.

The only things you want to get rid of are excess calories. Namely the refined foods - the components like bottle vegetable oils, flours, starches and sugar. Replace these with whole foods. You will then actually get more of these micro nutrients.

The recommendations for intermittent fasting is usually 2-3 days maximum in a week. With the 5:2 diet where you eat normally 5 days a week and space the 2 fasting days apart, it is a compromise that many people can do. You are allowed to have a soup (made with plenty of vegetables and some protein) or a very large salad with a little protein to keep you topped up with water soluble vitamins, minerals, amino acids and omega 3 and 6. (I would recommend you also add a little omega 3, Vitamins D, K2 and B12 because these are more difficult to come by. Cod liver oil, salmon, tuna and UV treated mushrooms contain vitamin D (the first 3 contain long chain omega 3 fatty acids). Natto, grass fed derived hard cheese and butter contain K2. Eggs and seafood are rich sources of B12.) You don't need to eat a lot of the below high quality proteins because they are very nutritious.

That should give your body all the materials it needs to function without many of the calories - those calories will come from your fat stores. (But you need to do a tiny amount of exercise 15 minutes of resistance training and about 15-30 minutes of hard cardio - to get your hormones protecting your muscles and stripping away the fat).

A more extreme version is consecutive fasting for 2-3 days in a week, with a 4 hour eating window, which makes your growth hormone and testosterone reach higher peaks to protect your body from breaking down too quickly. This makes the fast time very long because in 2 to 3 days you are fasting for about 20 hours. So you can lower insulin and keep blood sugar low which promotes growth hormone and testosterone release. On a shorter fast, with a larger eating window your blood sugar and insulin remain higher for longer which inhibits growth hormone and testosterone release for more hours in the day.

Intermittent fasting is not a magic bullet for fat loss because there is so much you can do to improve the nutrient profile of your diet. If you are someone that doesn't want to change much and are time poor it might be suitable for you. But make sure you are very discerning on what foods you eat when you are not fasting because you don't want to be cutting out food randomly that could make you become deficient in nutrients that you need.

Drop some comments if there are any specifics that you would like more information on. I am sorry it is quite a long response. I was not happy how many people don't want to look at the nutrition and just assume skipping a meal/s or cutting foods in a random manner is acceptable.