I generally ignored this paper in 2008 as it didn't look particularly interesting and seemed mostly about fast food bashing, where the fast food included a large amount of sugar and starch. A bit like a real life Supersize Me, but with genuine average food intakes provided and individual responses in ALT levels, a marker traditionally associated with liver damage, also provided.
If anyone wants to eat 285g of sugar a day then they deserve whatever they have coming to them. What they have coming is an ALT increase which correlates with either carbohydrate or sugar intake by three weeks in to the feast. Not with fat.
I found the lack of association with fat disappointing. Sweden is a country fairly replete with trans fat and a little arithmetic applied to Table 1 (LeenaS describes these as "hidden fats") suggests that trans fat intake went from about 6g/d to 24g/d during the over feeding period of the study. This is not quite at the level of Crisco poisoning but I was still disappointed to see no discernible association with ALT. Ah well, you can't have everything.
Now I remember Tom Naughton nuking himself with trans fats during Fathead to the point of lowering his HDL, but otherwise he developed no suggestion of metabolic syndrome. But then Tom engaged his brain before drinking bucket loads of fructose and desisted from such stupidity. The fructose trick is for anyone with more Spurlockian intelligence.
To go back to Sweden: Gross overfeeding with "fast food" elevates your ALT. This is sort of boring because no one in their right mind is going to eat that much fructose in a month, which sort of defines Spurlock.
But was anyone still awake by the end of Supersize Me? Remember how long it took him to lose weight on his girlfriend's vegan cooking?
Now the question is, does this translate across in to the Swedish ovefeeding group? Well that was answered by a follow on study looking at the participants two and a half years down the road.
They're still fat. On average.
Something breaks in a month of overfeeding with trans fats and sugar. That is fascinating. Now you could argue that the volunteers got the taste for junk food, that their fat cells got stretched, that they were already self selected for being comfortable with gaining weight to take part in the study etc. I'd like to look a little more closely at liver pathology.
Elevated ALT is traditionally assumed to indicate liver damage. But there might be circumstances where you make more ALT in each cell, especially if a lot of amino acid processing is going on, so get benign ALT elevation. No one had a liver biopsy so it was impossible to find out exactly why the ALT went up.
Now, from a pathologist's point of view, a fatty liver is completely reversible. There is nothing permanently damaged in each hepatocyte or in the structure of the liver. Hepatic inflammation is also theoretically reversible. Those old leucocytes can leg it out just as easily as they legged it in.
But fibrosis, that's a different matter. Fibrosis is there to stay. This is at the micro architectural level. We're not talking cirrhosis (yet). No pathologist expects a fibrosed liver to go back to normal. It may adapt, regenerate, keep you alive, yes. But it's not normal. It will never be normal.
I picked up a link to a mouse study in which they fed chow, Super Crisco (medium chain trans fats, what are they?) or Super Crisco plus fructose enriched sucrose via the drinking water. The rest of the diet is not in the abstract so who knows what else they did. But it was the Super Crisco plus fructose/sucrose in the drinking water which made all of the headlines.
Super Crisco appears to be bad for your waistline but may not, on its own, produce the irreversible changes in the liver seen in the mice who combined it with HFCS. As far as you can tell from the abstract.
A diet replete in trans fats and HFCS fibroses your liver.
Translating from the Swedish volunteers and these poisoned mice to our two film directors:
Tom Naughton should be fine with his low fructose high trans fat diet and Spurlock should have aged his liver by a few years (in terns of insulin sensitivity) during his month of self poisoning on trans fats because he combined them with fructose to push his ALT through the roof.
I'll try and put this in to a physiology context when a little more time comes my way.
BTW: A methodological note from the initial Swedish study which adds the "human element" to the mind set of the "scientists" running it:
"If the subject was not able or willing to ingest the hamburger-based diet at any stage, it was changed to whatever food the participant accepted with the highest priority to achieve the calculated caloric intake and also, if the study subject still found it acceptable, a diet rich in protein and saturated animal fat."
As always, it's nice when people nail their colours to the mast.
I see from Table 1 in the follow-on study that one man and one woman had actually reduced their weight to below their pre study weight by 2.5 years. I just wonder whether they were the ones who refused the trans fats of the hamburger diet and went with animal fat and protein to source their excess calories. No one is saying.
That human element gets everywhere!
EDIT: See Patrick's notes in the comments about the group leader from the hyperalimentation studies. A different impression from the published papers. There is hope for Sweden. Good.