[Dear J., you might find this interesting. -M.]
So... I'm normally pretty skeptical of nutritional fads and medical findings, because I often feel like it's not really grounded in good science. But I feel like I can recognize solid science when I see it.
My friend Eric Mueller recommended a book to me called The Obesity Code, in which the author (a kidney/diabetes specialist by the name of Dr. Jason Fung) advances the hypothesis that obesity is essentially a hormonal imbalance (high insulin levels leading to insulin resistance), and I find the claims impressive, consistent with my own experiences, and persuasive.
One key fact, supported by many, many case studies (Dr. Fung describes so many case studies that it starts getting tedious), is that your brain can adjust both appetite (calories in) and metabolism (calories out) and tries to balance them against each other. If you try to feed someone more food than they'd naturally eat, not only do they lose appetite and resist eating that much, but even if you do get them to overeat, their metabolic rates go up too. (I'm oversimplifying because there are multiple ways to body consumes energy, from raising your temperature to motivating movement to depositing it in stool.) If you decrease food consumption, metabolism slows too--not perfectly but pretty close, which is why obesity is something that generally takes years to develop instead of being something that can happen to you in a single month of really bad decisions in college. And it's also why trying to "Eat Less [calories], Move More" practically never results in long-lasting weight loss, even in studies where we measure the participants and know that they really are exercising more and eating less.
But the argument (as I understand it) goes that this metabolic homeostasis (keeping calorie intake and metabolism close to each other) is regulated by hormones (chemical signals sent to each cell of the body), and there's excellent evidence (detailed in the book) that the key hormone is insulin. High insulin levels tell cells to store energy; low insulin levels tell cells to release energy; insulin levels rise after a meal (especially carbohydrates without fiber), telling your body to store food. Normally that is fine, but here's the sticky point: when your insulin levels are high all the time from constant eating, your liver and muscles develop insulin resistance (respond less and less strongly to a given dose of insulin) but your brain, which regulates your appetite and metabolism, does not. Over a period of years or decades, your insulin levels get higher and higher as your insulin resistance in your muscles and liver get higher and higher (because more insulin is needed to do the job), but the parts of your body controlled by your brain get more and more inclined to store energy. Then if you ever manage to lose weight, your insulin resistance outside your brain is still as high as ever, so your body still keeps insulin levels high, so your non-insulin-resistant brain is still very willing to return your body to its previous weight.
I'm about halfway through the book so I haven't finished reading all the science yet, but it's obvious at this point what the conclusion is: in addition to eating fewer foods that boost insulin production and insulin resistance (i.e. eat fibers, whole grains, and avoid sucrose and fructose like the plague, especially soft drinks, because fructose boosts your liver's insulin resistance due to being metabolized only in the liver)--in addition to that, it's important to be hungry more often. 21st century humans spend waaaay too much time in a "fed" state (insulin excess) and often the only time we spend in an "unfed" state (insulin deficiency) is when we're asleep. For decades I've thought that you need at least 500 calories per day or so to prevent muscle loss--I'd been told that your brain can't metabolize fat, so your body winds up burning muscle to fuel your brain, but that turns out to be untrue. There is nothing wrong with occasional fasting, and the world record is a guy who (back in 1973) went 382 days without eating, under medical supervision, and came out of it much thinner but perfectly healthy and ambulatory. [ref: http://cristivlad.com/total-starvation-382-days-without-food-study/] So clearly being hungry isn't going to kill you or liquidate your muscles.
So that's basically it, apparently. Reduce insulin levels by eating fewer highly-processed, sugary carbohydrates, and by being hungry more often and for longer periods of time. (Dr. Fung recommends skipping or delaying breakfast, which is something I like doing anyway.) These are things, I think, which I can actually be quite good at doing, now that I understand specifically what I'm trying to accomplish. I've always been better at absolutism than moderation, and "don't eat right now" is a much easier message for me to get my head around than, "Eat right now but don't eat very much." (How much is "very much"? If eating is sort of bad right now, why am I eating at all? Etc.)
--
If I esteem mankind to be in error, shall I bear them down? No. I will lift them up, and in their own way too, if I cannot persuade them my way is better; and I will not seek to compel any man to believe as I do, only by the force of reasoning, for truth will cut its own way.
"Thou shalt love thy wife with all thy heart, and shalt cleave unto her and none else."
So... I'm normally pretty skeptical of nutritional fads and medical findings, because I often feel like it's not really grounded in good science. But I feel like I can recognize solid science when I see it.
My friend Eric Mueller recommended a book to me called The Obesity Code, in which the author (a kidney/diabetes specialist by the name of Dr. Jason Fung) advances the hypothesis that obesity is essentially a hormonal imbalance (high insulin levels leading to insulin resistance), and I find the claims impressive, consistent with my own experiences, and persuasive.
One key fact, supported by many, many case studies (Dr. Fung describes so many case studies that it starts getting tedious), is that your brain can adjust both appetite (calories in) and metabolism (calories out) and tries to balance them against each other. If you try to feed someone more food than they'd naturally eat, not only do they lose appetite and resist eating that much, but even if you do get them to overeat, their metabolic rates go up too. (I'm oversimplifying because there are multiple ways to body consumes energy, from raising your temperature to motivating movement to depositing it in stool.) If you decrease food consumption, metabolism slows too--not perfectly but pretty close, which is why obesity is something that generally takes years to develop instead of being something that can happen to you in a single month of really bad decisions in college. And it's also why trying to "Eat Less [calories], Move More" practically never results in long-lasting weight loss, even in studies where we measure the participants and know that they really are exercising more and eating less.
But the argument (as I understand it) goes that this metabolic homeostasis (keeping calorie intake and metabolism close to each other) is regulated by hormones (chemical signals sent to each cell of the body), and there's excellent evidence (detailed in the book) that the key hormone is insulin. High insulin levels tell cells to store energy; low insulin levels tell cells to release energy; insulin levels rise after a meal (especially carbohydrates without fiber), telling your body to store food. Normally that is fine, but here's the sticky point: when your insulin levels are high all the time from constant eating, your liver and muscles develop insulin resistance (respond less and less strongly to a given dose of insulin) but your brain, which regulates your appetite and metabolism, does not. Over a period of years or decades, your insulin levels get higher and higher as your insulin resistance in your muscles and liver get higher and higher (because more insulin is needed to do the job), but the parts of your body controlled by your brain get more and more inclined to store energy. Then if you ever manage to lose weight, your insulin resistance outside your brain is still as high as ever, so your body still keeps insulin levels high, so your non-insulin-resistant brain is still very willing to return your body to its previous weight.
I'm about halfway through the book so I haven't finished reading all the science yet, but it's obvious at this point what the conclusion is: in addition to eating fewer foods that boost insulin production and insulin resistance (i.e. eat fibers, whole grains, and avoid sucrose and fructose like the plague, especially soft drinks, because fructose boosts your liver's insulin resistance due to being metabolized only in the liver)--in addition to that, it's important to be hungry more often. 21st century humans spend waaaay too much time in a "fed" state (insulin excess) and often the only time we spend in an "unfed" state (insulin deficiency) is when we're asleep. For decades I've thought that you need at least 500 calories per day or so to prevent muscle loss--I'd been told that your brain can't metabolize fat, so your body winds up burning muscle to fuel your brain, but that turns out to be untrue. There is nothing wrong with occasional fasting, and the world record is a guy who (back in 1973) went 382 days without eating, under medical supervision, and came out of it much thinner but perfectly healthy and ambulatory. [ref: http://cristivlad.com/total-starvation-382-days-without-food-study/] So clearly being hungry isn't going to kill you or liquidate your muscles.
So that's basically it, apparently. Reduce insulin levels by eating fewer highly-processed, sugary carbohydrates, and by being hungry more often and for longer periods of time. (Dr. Fung recommends skipping or delaying breakfast, which is something I like doing anyway.) These are things, I think, which I can actually be quite good at doing, now that I understand specifically what I'm trying to accomplish. I've always been better at absolutism than moderation, and "don't eat right now" is a much easier message for me to get my head around than, "Eat right now but don't eat very much." (How much is "very much"? If eating is sort of bad right now, why am I eating at all? Etc.)
--
If I esteem mankind to be in error, shall I bear them down? No. I will lift them up, and in their own way too, if I cannot persuade them my way is better; and I will not seek to compel any man to believe as I do, only by the force of reasoning, for truth will cut its own way.
"Thou shalt love thy wife with all thy heart, and shalt cleave unto her and none else."
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