Wednesday, January 20, 2010

Science of Weight Loss

I have been wanting to post something like this for months and am finally getting around to it. As you all know, I watch a lot of documentaries and other programs concerning weight loss. I also read a lot about WLS and weight loss in general. This post is about some of the more scientific areas of understanding weight loss that enable me to wrap my brain around the subject.

First, there is the Harris-Benedict Equation. There is a site devoted to calculating this that is one of my links on the right side of my blog (called Caloric Intake Formula--although it is for expenditures too). It has been very helpful to me. I found out about this equation through my emails from Jillian Michaels--not personally, mind you, it was a listing-type deal :). If you aren't already familiar with it, the site states that the Harris Benedict Equation is a formula that uses your BMR [which you can also calculate on the site as well by simply inputting your height and age] and then applies an activity factor to determine your total daily energy expenditure (calories). So essentially, you plug in some numbers (you can plug in your goal weight, your current weight, or any number in between) to see how many calories EXACTLY you should be taking in and expending to maintain (or in some of our cases, to achieve) a certain weight. For the more math-minded folks, there is an actual formula too (you can find it on the site if you'd like), but it is a lot easier for me just to plug in the numbers. I like this formula because it tells me directly how many calories I should be eating and burning each day based on my height and age...and how many I will need to be taking in at goal when I get there. Once you use it a couple of times, it is really not that complicated to understand and is most useful and convenient.

Another interesting bit from science that I want to share is with regard to Leptin. Leptin has been referred to as the 'appetite gene' by scientists dealing with obesity studies today. It is attributed with controlling the impulse to overeat. Without this gene, people will desire to eat too much. In studies with mice (poor little guys--evidently they like to use them in weight-loss studies; I know I've blogged about their use before), mice without Leptin were always hungry and ate continuously. Fat mice and thin mice were distinguished from one another because thin mice had the gene and fat mice did not. The mice had the same environment, exercise, water, and food. They could be cousins or brothers and sisters with thin mice, but Leptin was the only difference. Leptin tells mice and humans that we've had enough. Without it, there's no signal from the brain to stop eating. Many other genes help determine appetite in humans too. And from all of the studies of these, science is showing that it is not greed or lack of willpower but genetic makeup that makes us want to overeat. Years ago, Leptin and other genes developed to help fight famine, but with today's fat diet and couch-potato lifestyle, these helpful genes have become things that could kill us. Obese people are obviously aware of what they are doing to themselves when they gain weight, but science has shown that even though they know that they will feel wretched if they eat more) they do it anyway because the drive is so strong. Where one person eats and is perfectly content not to eat again for five or more hours, people without the Leptin gene are looking for another meal to eat in two hours. It is more than willpower to eat less. Therefore, as one doctor stated, "People can either accept Leptin as the appetite gene or think that obese people are weak willed, fat, lazy, and disgusting" and that the obese "are not as good as they [the thin people] are because they're thin." This area of study makes a lot of sense to me and is part of the theory that many weight loss surgeons and staff use.

And to briefly review one other area of scientific tackling of weight loss, I have also heard about advances in the Battle Against Head Hunger. In fact, cutting-edge technologies (and even surgeries) have been developed and are addressing it (although they are not perfected at this point).

Saying all that, nothing I mentioned above discussed metabolism. We hear a lot about this. So how does that factor in to the HB Equation (I REALLY want to know this since the formula that is constantly touted is 'calories in, calories out'--not that this isn't right, just that I am curious about this)? And what about how it fits in with the Leptin gene? If metabolism truly has nothing to do with it, then are we obese people truly eating more calories each day than our skinny counterparts? Sometimes that's hard to accept, but I, for one, haven't done a quantitative study on that particular subject--so it's not for me to know or say.

What about things that have been scientifically shown to miss the mark? Some things that haven't been found as effective at permanent weight loss are body wraps, colon cleansing, and steam rooms (to shed water weight, which will inevitably come back on since we have to drink to live). Also, as my surgeon told me, the things that many weight-loss drugs will do to a person (side effects and such) are more harmful by far than surgery. Of course, we definitely want to avoid anorexia and bulimia nervosa. My understanding is that some bandits see WLS as an opportunity to engage in those types of behaviors more easily. Not to sound preachy or anything, but we all should try to keep in mind that we did this for our health (in addition to other things, yes), and starving and vomiting will hurt, not help, in bringing about more healthy lifestyles.

So I guess we have to stick to what we do know at this point--simplify our understanding that it is, at least to some extent, all about intake and expenditure of calories (guided by BMI, BMR, and the Harris-Benedict Formula). Also, drinking water, getting fiber, taking vitamins, trying to get as close to a normal BMI as possible (and if inside normal, my Wii told me the other day that a BMI of 22 is supposed to be the BMI number for optimal health--although on whose BMI scale? :) ), and exercising with cardio and weights (excercise has been labeled by several to be the best medicine for the body) are the tried and true approaches. And thank goodness for the band, of course, to help with backsliding and to remind us that we need to stop chowing down sometimes (it's our surgically devised Leptin substitute, I guess :) )!


  1. Interesting stuff. I plugged in my numbers and it said my BMR should be about 2400 calories to maintain less 500-1000 calories to lose weight. I wouldn't eat anywhere near that! I try to stick to around 1000 calories a day. Not sure if that's good or bad. I hear ya on the wii thing - 22BMI - I don't flipping think so! I'm aiming for 25.

    Em :)

  2. Hey, thank you for that post, its very very interesting! Im going to go check it out, I love that Leptin thing definatly explains alot to me, I think it also has to do with Insulin Resistance and stuff like that.

  3. Cool thanks for posting that info.

    One thing I would like to know more about is how people with high levels of cortisol that leads to belly fat and stress symptoms (H BP, etc) can lower their cortisol.

    I wonder because I have read lots of studies that show kids who grew up in abusive or dysfunctional homes have higher cortisol levels as adults and more highly developed neural pathways for the cortisol to flow. So they're hardwired to produce a lot of it quickly in times of stress.

    I think I am one of those people! I am sure exercise will probably be the key. Natch, it always is!

  4. Emma, you can just go straight for the goal numbers (even your crazy lowest low goal)--just plug them in and voila (you'll see what you have to do when you get there--or where your calories will be (they'll probably be closer to the 1500 range if they're anything like mine).

    Lynette, do you know that you were banded three days before me (a year later, but still :) )?!!! Super cool! And yes, I thought the same thing when I discovered the Leptin info.

    It always seems to, doesn't it, Brooke? It all goes back to exercise. The dreaded 'E' word! :)