The Fats You Don’t Need to Fear, and the Carbs That You Do

10 weeks of changing your diet in general will probably lead to weight loss as long as you're not increasing your total calories, but that doesn't mean that the diet is sustainable long-term. If you live on say, a few donuts a day, you'll lose weight, but it'll also give you terrible sugar crashes and you won't be able to focus. You'll be irritable. It will really suck, and you'll either end up eating more or seeing your quality of life suffer.

What is interesting is the mechanism that causes low glycemic food to digest slower. It's the fiber! Processed Uncle Ben's has .6 grams of dietary fiber per serving while brown rice has 3.5 grams per serving. For the same reason brown rice takes much, much longer to cook breaking down the cellulose to make it palatable, brown rice takes much, much longer to have it's energy absorbed into the blood stream, the fiber.

When a person eats low glycemic therefore high fiber foods, they are getting the same amount of satiation per same quantity of food, but that fiber is passing through without being absorbed. So, people eating low glycemic foods are consuming less calories for the same level of satiation. That is the 10,000 ft view but it more complicated than that because different foods have different levels of satiation based on many things that are more than just physiological but also psychological.

The article says that high blood sugar levels lead to weight gain which isn't entirely true in most people. High blood sugar levels while the liver has stored as much energy as it can in the sugar analogue glycogen leads weight gain and eating low or high glycemic foods doesn't matter.

I can only speak from my own experience– but I'm a tall, skinny guy and if I don't eat for longer than a couple of hours, I start getting low blood sugar symptoms. My heart starts racing and I have trouble focusing or sleeping.

I did some reading about it, and I can't remember the exact science, but I think I read that if your blood sugar levels are too low, your brain worries that you'll go into a coma and it'll try to keep you awake.

Now that I wrote that down, it sounds a little pseudosciency, but that's consistent with my experience. Would love to hear from anybody who has a better understanding.

It tends to ignore the fact that energy expended by metabolism is a black-box function that takes energy absorbed from food as just one of its input parameters.

If you restrict calories below a threshold (that varies by individual), the body will flip genetic switches to enter famine survival mode. It will adjust metabolic functions to slow down weight loss by any means possible. When the restriction ends, some of those switches do not get toggled back to their previous state. So if you have ever tried a diet that included severe calorie restrictions or extended fasting, you may forevermore find it much easier to gain weight than lose it.

So if you want to go by the thermodynamic hypothesis, it is far safer for you in the long run to hold your diet constant and either increase exercise or thermogenesis (i.e. live through a winter at one of the poles).

Channel swimmers burn about 40 Mcal of energy. Marathon runners burn about 3 Mcal. But their bodies will prefer to use up all glycogen stores before digging in to body fat, and now some will eat glycogen gel during the event to avoid "hitting the wall" entirely. Fat-burning is maximized only after depleting glycogen, or when exercising below the aerobic threshold (and possibly also below the lactate threshold), between 60% and 70% of your maximum heart rate. Obviously, this would ordinarily set a hard limit on the number of kcal you can reasonably expend via exercise to lose body fat.

Thus, the uncanny effectiveness of ketogenic diets and "bonk training". Those practices intentionally deplete glycogen stores beforehand, so any exercise done in that state burns more body fat, regardless of your exercise intensity. Ordinarily, you could have 1500 kcal or more of glycogen stores. That's enough for 15 miles of running, or 2 hours of cycling. And that's a lot of exercise to do before you start to get more permanent fat-loss results.

It is much easier to eat just enough protein to serve the short-term needs of your body, eat the remaining caloric requirement to avoid switching to starvation mode as fat, and avoid all carbohydrates like the plague. Your body converts only as much protein as it needs into sugars, but not enough to replenish its glycogen, and switches to using fat as its primary energy supply, so any additional kcal you expend are coming directly from adipose reserves. (This sort of lifestyle may have unintended side effects.)

People don't want to just "lose weight". When they say that, they usually mean "lose fat". And that goal is a lot more complex than just kcal in minus kcal out.

We still don't fully understand how diet, exercise, metabolism, and appetite work together to produce visible effects on the body. But we do know that a single dietary strategy will not work for everybody, particularly the "just reduce calorie count" strategy.

Here are some GI values for rice from the Mendosa GI list... http://www.mendosa.com/gilists.htm

The nominal GI of white rice is 73. But various brands and preparations can cause the GI of NS white rice to vary from 43 to 90. Long grain varies from 50 to 76. Uncle Ben's in a pouch runs around 48.

The nominal GI of brown rice is 68. But again, brand and preparation introcuces much variance, from 50 to 87.

The nominal GI of converted boiled white rice trends lower at 38 (Uncle Ben's) but can run as high as 87.

However from an authoritative article of 1000 foods in Diabetes Care from 2008, the GI of white rice is 89 and brown 50. http://www.health.harvard.edu/healthy-eating/glycemic_index_...

In the end, it seems you have to be very careful about exactly which products and preparations you're comparing.