Wednesday, June 10, 2009

Intermittent Fasting: Switching from Alternate-Day Fasting to Condensed Eating Window

Intermittent Fasting: Switching from Alternate-Day Fasting to Condensed Eating Window
Thankfully, coffee has zero calories. (Photo by Erik)

Time for another update on my intermittent fasting experiment, which has been running for 10 months now. As you probably know, intermittent fasting means alternating periods of eating with periods of fasting. The length of these periods varies depending on the type of intermittent fasting one does.

So far, I've been doing the 24/24 hour cycle, meaning that I eat for 24 hours and then fast for 24 hours. This is known also as alternate-day fasting (ADF) or every other day fasting (EOD). It has worked very well for me: the fasting periods are short enough for the hunger to be very bearable but long enough to (hopefully) see some long-term benefits such as improved insulin sensitivity and reduced mitochondrial damage. If you want to read more about what intermittent fasting is like in practice, I've written blog posts on my typical day and my typical high-fat, low-carb meal.

Starting yesterday, I've switched my eating schedule a little and experimented with another version of intermittent fasting, known as the condensed eating window. Essentially, this just means eating only during certain hours of the day. The difference to the 24/24 hour cycle is that the eating period does not continue onto the next day. A popularized version of this is the Fast-5 Diet, which promotes an eating window of 5 hours.

The way I do it is that I fast during morning and day and then break the fast when I get home from work. If I stop eating at midnight, this results in daily fasts of 16-18 hours and eating windows of 6-8 hours. So no breakfast and lunch but a big dinner and evening snacks.

There are various claims as to whether this kind of diet is healthy. One study suggested that eating only one big meal instead of the usual three may result in poorer insulin sensitivity and glucose tolerance and slightly higher blood pressure. On the other hand, body weight and stress hormone levels were reduced.

As discussed in the links above, the methodology of the study seems somewhat suspect. In any case, I won't be eating just one huge meal, but spread my energy intake throughout the 6 to 8 hours. For weight loss purposes eating only once per day may work, but I'm attempting to maintain my weight.

For more information on diets and health, see these posts:

Intermittent Fasting: Understanding the Hunger Cycle
Low-Carb vs. Low-Fat: Effects on Weight Loss and Cholesterol in Overweight Men
The Effects of a High-Fat Diet on Health and Weight: Does It Raise Cholesterol?
How Does Fructose Affect Triglyceride and Cholesterol Levels?

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3 kommenttia:

M June 13, 2011 at 4:07 AM  

Hi! I suffer from auto-immune disease. The first symptoms started in childhood with obesity/metabolic syndrome and chronic depression, and in adolescence psoriasis. Now, twenty years down the road I have rheumathoid arthritis, like most people with psoriasis usually develop.

I've managed to lower my weight from morbid obesity to overweightness by eating healthier and less, but I still struggle. My pot belly and lack of energy (to say nothing of the skin disorder, chronic depression and rheumatism) are a constant reminder that the battle is far from won. So I try to live very healthily and I've recently taken an interest in IF, because of its claims that it improves your metabolism and therefore aids weight loss; and that it's generally anti-inflammatory.

However, from testimonies I've seen on the internet the most sucessful cases of weight loss are almost invariably very young, very healthy athletes, with the muscles to prove it; whereas regular folk who are not athletes only manage to keep their weight down through the old-fashioned method of cutting calories and perhaps banning simple carbs as well - regardless of doing IF, although fasting helps to cut down calories and total intake of food.

I'm beginning to doubt also most claims that anything that helps your metabolism will by definition lower your weight. If that were true healthy eating would be sufficient, and it isn't; calorie restriction is the only thing that seems to work for me. It all seems like a pointless sacrifice.

What are your thoughts? Is going hungry the only thing that actually works for those of us who are simply not healthy, young and strong enough to exercize like athletes? And what are the long term effects of eating a sub-nutritious diet purely for the weight loss? In the short term I'm sure the weight loss is beneficial, but if one does it for life won't that hinder one's health because one is simply not eating enough?

JLL June 13, 2011 at 10:42 AM  


There are definitely some people whom IF seems to help lose weight, but as I've mentioned in other posts, it was not difficult for me to maintain my weight even on a 24/24-hour cycle. That's why I don't think IF is any guarantee for weight loss, it really depends on how you do it.

As for CR, I don't think it's necessary to go hungry to lose weight. For the overwhelming majority of people that I've seen trying various diets, low-carb has been the most efficient and probably easiest way to actually lose weight.

Cutting out grains and processed vegetable oils (and most other processed foods, really) is in my opionion the most important step; the rest is tweaking and experimenting. Some people stay thin even on a high-carb diet, as long as they eat the right carbs (like starchy tubers). What is your diet like at the moment?

I'm not a big believer in doing aerobic exercise for weight loss, but lifting weights would probably be a good idea, if you can do it.

"In the short term I'm sure the weight loss is beneficial, but if one does it for life won't that hinder one's health because one is simply not eating enough?"

Eating enough food or getting enough nutrients? You can certainly get by with less than 2,000 kcal per day, but you'll probably need to take some supplements to cover all grounds.


Anonymous August 17, 2012 at 1:16 AM  

Hi M - the symptoms you've described are all classic symptoms of magnesium deficiency. No doctor will tell you this (if they know). The average adult needs about 600mg of magnesium per day. This fluctuates from day to day, depending on what you're doing, eating, how much stress you're experiencing, but the 600mg is the average daily requirement. Best form: magnesium chloride (known as 'flakes'). Second best is the old-fashioned way - magnesium tablets taken throughout the day. You'll find all of your symptoms, including the arthritis and especially the depression, melt away.

All the best to you.

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