And Lustig responds to those criticisms here:

http://www.kqed.org/a/forum/R201104211000

Key takeaway is that Lustig doesn't make any claim that you can't get fat by eating too many calories, regardless of the source. Lustig's research is on the metabolic pathways for fructose and glucose, and they are substantially different.

I'll listen when I have some time later. Does he also address the dose dependent problem in his cited studies? Of course if I'm drinking 6-7 sodas a day that's generally going to be a problem, but it doesn't mean sugar is evil. Too much water can kill me also, but I don't see people saying water is evil.

Like I said, he talks about metabolic pathways, which are independent of dose, though not your body's current state of glycogen deficiency.

He also speaks to the effect of insulin resistance, and how the very rapid metabolism of fructose in the liver (7x faster than glucose) can lead to insulin resistance. Insulin spikes redirect calories eaten directly to fat, without them ever being metabolized into energy. As a result you gain fat and have less energy available, leaving you both fatter and hungrier.

Thanks for giving such a great summation. This was the key point for me from Lustig's presentation.

Essentially, if you treat sucrose and fructose as a condiment, rather than as a key source of kCal, you will be consuming simple sugars, protein and fat, food that actually nourishes and sates you directly, versus sucrose and fructose that in high doses simply transform to fat.

Per Lustig, it's important to differentiate between starches found in bread, potatoes etc., that break down to simple sugars like glucose that are metabolized directly by the body, and added sucrose and fructose that are metabolized in the liver to fat. For people saying that our carb consumption was the same back in early 20th Century, take a look at how much of that was likely breads and the like, versus the highly sweetened cereals of today.

edit: added a para on why looking at 'carbs', misses Lustig's point.

Intake is the key point in the entire argument for me. The dose makes the poison, and at this point we're arguing over whether it is healthier to poison ourselves with excessive calories from fat or excessive calories from carbs. If you don't eat too much, you don't have a stake in the argument at all.

Not really. It depends on each person's metabolism. I know people that get fat just by having regular desserts for a few days, and others (generally very young) that can eat anything until they burst without moving the needle.

In general, you can't trust self-reported data, especially not data reported to social acquaintances. Not only do people underreport how much they eat (it's the norm, even for people who aren't overweight), they don't do a good job of measuring their weight and reporting weight loss or weight gain. People really do say and believe that they've gained five pounds in two days, or lost ten pounds in a week, when it's clear they are just measuring fluctuations that have nothing to do with muscle or body fat.

There is no such thing as 'metabolism': just body mass, muscle mass and activity.

Big people burn more calories even when still. Active people burn more than still people of the same size. Muscular people burn more calories than the non-muscular as they have to feed their bigger muscles.

In sealed room tests fat people use more calories than thin people.

Skinny people who can eat anything they want without putting on weight tend to be very fidgety - they never keep totally still. Just wiggling a leg all day can use a large amount of energy.

"Skinny people who can eat anything they want without putting on weight tend to be very fidgety - they never keep totally still. Just wiggling a leg all day can use a large amount of energy."

Hm, this is interesting. I've never heard that before, but it seems intuitive. Do you have any sources for that idea? (Not that I'm challenging, just curious.)

In the literature its referred to as N.E.A.T. Non-Exercise Activity Thermogenesis

Many people's body's response to overfeeding is to up NEAT, up fidgetyness. But not always. Your body thinks getting fat is a good thing. Famine used to be common. When dieting almost everyone down-regulates NEAT. On a severe diet you feel like being very still.

Awesome... I will tell my coworker who is always complaining about my fidgeting legs that I'm exercising ;)

"There is no such thing as 'metabolism': just body mass, muscle mass and activity."

Those factors are not enough. The human body has many more important factors in play there, like hormones, intestinal flora, and so on.

The reasoning in that line shows the classic misunderstanding that has led us here. As Taubes says, saying you get fat because you eat too much doesn't explain anything. Of course you need to eat more calories that you expend to gain weight. But why do people do it, and why didn't they do it before?

Taubes says we eat too much because we eat carbs. If people had eaten a carb-free diet since 1970 we wouldn't be seeing that spike in calorie intake. Therefore the fact that calorie intake increased is in complete support of Taubes and Lustig's ideas.

Carbs increase insulin secretion, which encourages fat cells to take in blood sugar and turn it into fat, and discourages the body from burning fat for fuel.

What if we increased carb consumption far above the levels of today (from 43% of our diet to, I dunno, 54%)? Would we be even fatter than we are now?

https://docs.google.com/viewer?url=http%3A%2F%2Fwww.cnpp.usd...

History tells us the answer. In the early part of the 20'th century, we ate nothing but carbs. We weren't fat.

Were the early-20th-century carbs the same carbs as today? (Corn and potatoes aren't the same as sugar-cane and HFCS.)

You might try reading the report I linked to.

The big difference is that we eat more calories, less carbs, more fat and more sugar.

Your report just has "Carbs" - nothing to do with what sort they were. That could be flour, sugar, or potatoes, and they stay relatively constant, there's no decline (p18).

There's a big increase in the amount of fat consumed, but I suspect a large part of the difference is going to be lifestyle, too. Around the turn of the century people walked a lot more and did a lot more manual labour.

See table 4 and 5. It doesn't give breakdowns of sugar vs HFCS or corn vs wheat, but it does separate sweeteners from potatoes from grains.

Regardless - total calories went up. Carbs stayed almost constant in absolute terms (a slight decrease) and decreased in relative terms. Fat increased in both absolute and relative terms. I guess carbs must be the culprit!

Ok, I see that now, and it fits with what I know - if your blood glucose is saturated, then any extra fat and sugar you eat goes straight to your arse.

Interesting that whole milk dropped off so sharply in the 1970s and 80s - about the time that 'fat is bad' started up? From what I've read, low fat milk contributes to heart disease too - something about the level of fat-soluble vitamins?

that doesn't seem to be a very good criticism at all. he completely misses Lustig's point, skews the argument and tries to obfuscate his own lack of expertise with buzzwords and shallow analysis.