more thoughts on fasting

I was studying my nutrition book tonight and just happen to get to the place where it discusses Feeding and Fasting (by coincidence, this is 3 days after I tried a fast). The first 4 hours after eating is the Absorptive State, where dietary nutrients are absorbed. Glucose is the body's major source of energy.

Then from 4-24 hours is the Postabsorptive State. Here dietary nutrients are no longer absorbed. The body's source of energy is supplied by the breakdown of store energy, primarily glycogen supplied by the liver (about 75% of the glucose is supplied this way). Also some fat is burned. "Some scientists believe that maintaining the human body in the postabsorptive state may have health benefits." This is based on studies of monkeys and rats that show that calorie restricted (not starved) animals live longer, and look younger and healthier at a given age than the normally fed animals.

From 24 hours to about 1 week is the Acute Starvation stage. Here I think body fat supplies most of the energy, but muscles (lean tissue) also contribute to the production of glucose (by supplying amino acids, lactate, and glycerol). Ketosis also starts up. This is where the muscles, brain and kidneys can convert fatty acids and some amino acids to glucose.

Then you go into Prolonged Starvation, where the body relies on fat and ketones for energy.

During my 48 hour fast, The first 36 hours were fine. There were 2 night's sleep in there so lots of rest. I felt much weaker after that. That must have been when the liver-stored glycogen ran out, and the Acute Starvation phase started. I didn't enjoy this phase and can't say I have any interest in repeating it, unless I have some health reason and am in a position to completely rest during the fast. My muscles felt tired for a day after I started eating. They must have been depleted of energy even 24 hours after I started eating. Also I wonder if I lost lean muscle mass. I don't want to do that. I guess I'll have to reread Dr. Fuhrman's fasting book. I don't recall what the benefits of fasting for more than 24 hours are if you are healthy. I can see where 12-24 hour fasts are probably beneficial, and doing a daily fast between dinner and breakfast of, say 15 hours, is probably beneficial. That sounds good enough for me.

Fasting review

Today I ended my fast at 4 pm. That was about 48 hours after starting. I was definitely more tired and low-energy today. I was tired driving so didn't think that was so safe (I'm on a road-trip with a companion). I only drove 2 hours, and that was after working 2 hours, so I needed a nap. After driving I napped and felt fine, so I could have worked it out with better planning. Still, I'm not sure you should drive after fasting more than one day. Driving on day 1 seems fine.

After settling into our B&B, I decided it would be good to end the fast. I was tired and weak, and wanted to get some food in my body so I'd have energy tomorrow. I didn't want to start breaking the fast tomorrow when I'll need energy right away. Plus I need to eat more tomorrow and get even more energy for mountain biking on Sat. For breaking the fast, Dr. Fuhrman recommends steamed zucchini or other easy-to-digest vegetables. Well, I didn't have the energy to go out and get veggies to steam (in the microwave), so I just ate an apple. It's not like I fasted for 10 days, and need to learn to digest again. It was just 2 days. A few hours later I had half a can of soup: Dr. Fuhrman's Morrocan chickpea soup. Beans aren't the easiest thing to digest, but it was a small amount and I feel fine. I'm not eating again until breakfast so there will be plenty of time to digest the beans. Then I think my options at breakfast will be oatmeal and fruit. Lunch and dinner will probably just be fruit or salad, because I'll be at restaurants. But I'll bring another can of soup and eat that at the office if I need to. Then tomorrow night, I plan to go to the grocery store to get food for the weekend. If I need to eat then, I will.

Oh, so what do I think of fasting? I don't know. One day is easy. Two days is kind of painful for me. I don't like feeling tired and weak. You definitely have to stay home and do nothing after day 1. I could see fasting from 6 pm one day to 7 am 1.5 days later, so 37 hours. That feels good and cleansing I guess, and doesn't impact my life too much. I could see skipping meals on travel days when you are just sitting on airplanes or in the car and not doing much, and there is no good food to eat anyway (unless I bring it myself). I could see skipping meals when you are out and about and there is no good food to eat anyway (unless I bring it myself). So I could see incorporating shorter fasts when it's inconvenient to eat anyway. That means you can get away with less planning. But if I'm doing something physically active, I need to bring food.

fasting

Dr. Fuhrman recommends occasional fasting to maintain health. The break from digestion allows the body to detoxify and repair cells and tissues. I'm normally too active to want to rest all day, as fasting requires. I'm on a 2-day road trip with a companion so I thought, maybe this is a good opportunity to try a fast. I'm also hoping maybe it will help me get rid of this cough that has lingered since I got my cold almost 2 weeks ago.

So I fasted today. It went fine. I napped while companion drove, and that rested me enough for when I drove. I got hungry at dinner time but I'm not hungry anymore, which is a surprise. I was tired walking up the stairs with my suitcase, but I'm fine just sitting here playing on the computer. I wonder if I'll make it through tomorrow. I have to do some work tomorrow which is just mental, but that might be affected by the fast. Plus I might get hungry and not have the will to continue the fast. I'm not good at suffering through things. We'll see. I definitely have to break the fast on Friday because I have to socialize with strangers all day and go out to breakfast, lunch and dinner, and give a talk.

Fasting certainly made the travel preparation easier. I could see doing this on airplane trips, where you are also just sitting around and there is no good food to be had anyway.