> Here's the original article. http://www.nejm.org/doi/full/10.1056/NEJMoa1007137

Not available without subscription.

Even so, the media described in the abstract makes no mention of body composition; without that, there is no way this study can be considered adequate, let alone "impressively well done".

> Your liver has glycogen stores on board that will keep your blood sugar rock steady

Your reply is confused. There are two different points that you are conflating.

One is in regard to keeping blood sugar steady to prevent binging by AVOIDING high GI foods; the other is performance-related, and the NECESSITY of using high GI foods in specific instances.

> for the first 20 miles of a marathon

All you're saying is that if you carb load in advance, you will have glycogen until you run out of glycogen.

You're incorrect about "rock steady". Typically, blood sugar will actually spike at first, as the liver releases glycogen / glucose at the onset of exercise. And guess what happens following a spike...

> Unless you are exercising at a heart rate of 160-180 for 2.5 or more hours, this is useless trivia.

I specifically mentioned sustained cardiovascular exercise AND the Tour de France in regard to this. I give specific examples, and you scoff and say it wouldn't matter -- unless someone were doing something I specifically mentioned as an example. Are you objecting just for the sake of objecting?

By the way, heart rates are generally lower (in the 140 range, not counting time trials and climbs) and eating is fairly continuous in the TdF.

> Normal adult human brain uses, 120 g to, maybe, 220 g of glucose per day. At the outside, that's 750 Calories.

Is this supposed to be an objection? Also, your math is wrong, unless you're using some kind of magic low-calorie glucose (220 x 3.81 = 838).

If you're eating sucrose to get glucose, double the calories. That's a lot of sugar.

Also, things like playing chess or programming all day are a lot more mentally taxing than "normal" activities.

If you know of studies with either group, I'd love to see them.

> These facts about elite athletes do not bear on

You apparently missed where I specifically cited Phelps's herculean effort.

The only difference is the scale; I used Phelps as an illustration of what I stated at the top: You can't separate diet from activity. I'm not sure how you managed to miss every point and misconstrue every example.

> A far more useful factoid is that your glycogen stores are depleted overnight,

I mentioned this already in passing.

> so a 2-3 hour cardio session in the morning will force you to burn fat.

Anything increasing metabolic demands will result in increased oxidation of fatty acids even if you aren't fasted.

> (No, it won't burn muscle).

That's sheer nonsense. The body is already in a catabolic state after fasting, and adding 2-3 hours of cardio will absolutely burn muscle.

> Are you saying they loaded these cats with fructose?

Low-protein, low-GI diets can well be high in fructose. Do you have the food diaries?

> If they did, then these results are even more impressive, because we would expect a high fructose diet to promote fat gain.

They gained weight.

> First, this is why we enroll more than one patient. The noise averages out.

Once again, you missed the point. If a certain diet makes it very likely that people will cheat, you can end up getting a lot of dropouts (as they did) and the ones who stay in will be shifted toward the higher end. This makes the entire result set suspect.

> Two: the unit of measure was kilograms

Do you get points now for stating the obvious?

From the article: "The average weight regain among all participants was 0.5 kg". I took the liberty of translating that into about a pound.

> they quite nicely demonstrate sufficient granularity to appreciate signal

I already proposed the factor of water retention which would quite plausibly account for a kilo of difference.

> See Table 2 of the study.

I can't see it, but I can read the description, if you mean Figure 2:

"Panel B shows the change in weight for each of the dietary groups during the weight-maintenance intervention, adjusted for body-mass index at randomization, weight loss during the low-calorie-diet phase, sex, family type (single-parent family, two-parent family with one parent as participant, or two-parent family with both parents as participants)"

Absolutely nothing about body composition. It's just weight and BMI. They don't determine body fat percentage, lean mass, water weight gain.

It's also amusing how all the points got sucked out of my post and went into yours. I assume people saw "I'm also a doctor" and assumed that an argument from authority was valid. And you're not even an authority when it comes to sports medicine, which is the bulk of what I was referring to.

That's pretty disappointing, but I suppose the average reader of HN has even less knowledge about these things than you. Even so, your reply was obviously objecting spuriously and the rest was either repeating my points or stating the obvious. Very weak.

Being a bariatric intern has no bearing on sports medicine; it's practically the opposite end of the scale. You're concerned with gross measures like BMI. Do you even care about a kilo of difference on an obese subject? Yet for this study, with figures that small, body composition is the only way to figure out if it's relevant. A couple pounds of "weight" is meaningless.