“More Efficient Weight Loss ?”

A few weeks ago, right after the PMC, I started thinking about how the body gains and loses fat. My understanding of the process was very basic, and could be summed up as, "Sugars that aren't needed to fuel the body right now are converted and stored in the fat cells. When the body needs more sugars, the organs release what sugars they have stored first, and then the fat cells start releasing their contents back into the bloodstream, which is when weight is lost. So increased exercise without an increase in diet typically results in more fat converted to fuel, and therefore a loss of fat-weight."

That's the "basics," in the extreme, but is essentially correct (I've read a lot more about it since then).

What I specifically became curious about was the process of converting stored fat back into fuel for the body, and how this process might be made more efficient for someone who is already doing significant exercise (like, uh... me). Assuming I have ample "stored energy reserves," is there anything I could do or some food I could eat which would cause my body to convert more stored fat into energy than it would otherwise, during exercise?

That last part of the question is perhaps the most important. I'm not looking for a miracle. I'm already doing significant exercise (my training rides are almost fifty miles long), what I would like is a way to make the fat-burning side of that exercise more efficient. What made me think about this is that when I'm on a long ride, I still have to supplement my energy reserves with Gu, PowerGel, fruit or whatever. If I don't, I bonk and can barely finish. This is in spite of the fact that I still have plenty of fat reserves to burn. So, if there were some food I could eat (or drink) which would cause the body to burn fat even a little bit more quickly, I wouldn't have to eat as much while riding and would lose weight a little bit faster.

I'd be happy with an improvement of just 2 or 3%, anything better would be "gravy."

I mentioned the idea to Corinne, and then to my dad and Art (my brother-in-law). None of them knew any more about the metabolic process than I did, but they all understood what I was suggesting and agreed that it seemed like a good idea. "You're already doing the work, and the fat is there as a stored energy reserve, so it would be great if you could use more of that stored energy while exercising."

A few days later, I mentioned it to Brian Andresen. He knew a little more about metabolism than I did, and, perhaps more importantly, suggested a couple web pages as good starting points to learn more about it for myself. The first link is the one he suggested, followed by some I found for myself (one of them is also advertising some product or another... just ignore that and consider the facts they present):

• A general overview of the major metabolic pathways
• Hormones, Diet, and your Metabolism
• The chemical logic behind ... fatty acid metabolism

Now I have a slightly less basic understanding of at least the specific metabolic processes I've been thinking about: Insulin and glucagon (two hormones with some fairly obvious mnemonics to help remember their functions) control the storage and release, respectively, of fatty acids and glycerol.

Insulin is a hormone released by the pancreas when blood sugars are high, and causes the adipose tissues to store more fatty acids and sugars. Thus the first mnemonic: insulin "expands your fat cells," and as more fat makes you feel warmer, so "insulin insulates." (Hey, it works for me.)

Glucagon is a hormone released by the pancreas when blood sugars are low, causing the adipose tissues to release fatty acids and glycerol back into the bloodstream for use as fuel by the rest of the body. Thus the second mnemonic: glucagon is released when "glucose is gone."

So there are two processes I'm interested in: the release of glucagon by the pancreas and subsequent reception by the adipose tissues which triggers the release of fatty acids and glycerol for fuel, and the conversion of fatty acids and glycerol into energy by the muscle cells during heavy exertion such as my long bike rides.

That's where I'm at so far. What I don't yet understand is which process I want to be more efficient. Do I want my pancreas to release more glucagon during the same amount of exercise, which would therefore trigger a stronger reaction in the adipose tissues? Do I want the hormone receptors in the adipose tissues to be more reactive to the same level of glucagon? Perhaps the fatty acids secreted back into the blood stream by the adipose tissues are not the most efficient fuels during heavy exertion, and what I need is some way to improve my usage of this fuel?

Remember, my goal here is to find some way to use my own "stored fat" as an efficient fuel during exercise, so that I need less supplementation.

Still researching, but if you happen to know anything about this topic I'd love some input. (I know there's at least one doctor reading...)

I meant to start writing about this a week ago, but a visit to Daniel's page revealed that he had just started writing about something very similar! That sort of took the wind out of my sails for a little while, especially as it's not the first time this has happened (for example, he posted his first thoughts on RSD just as I was thinking about ways client applications could auto-configure themselves to work with Conversant sites and weblogs).