So blares the headline at the BBC news article the other day. What really annoys me though, is that this is tabloid medicine at its worse. Actually the “science” isn’t a lot better to be honest. I decided to investigate further. This link gives more detail on the story (though not enough by far): http://www.bidmc.org/News/InResearch/2009/August/LowCarbDiets.aspx
So I ask you, since when did a 12 week experiment, satisfy the desire to investigate the “long-term effects on vascular health.“ Mice only live a few years, so doing a whole lifetime study and actually measuring what counts wouldn’t be unreasonable, i.e.: actual mortality rates rather than guessing the outcome and quality of life (measured by activity levels say). I say guessing because as you’ll see, most of the increased factors they normally associate with heart disease were absent.
Before I get into that though, here are some details missing from the BBC article, on the actual composition of the diets. They only studied 3 permutations it seems:
- a standard diet of mouse “chow” (65 percent carbohydrate; 15 percent fat; 20 percent protein);
- a “Western diet” in keeping with the average human diet (43 percent carbohydrate; 42 percent fat; 15 percent protein; and 0.15 percent cholesterol);
- a low-carb/high-protein diet (12 percent carbohydrate; 43 percent fat; 45 percent protein; and 0.15 percent cholesterol).
They don’t however say how the percentage was split up. I assume it was calories, but it could have been weight or scoops maybe?
Why scientists such as these fail to do a thorough job is beyond me. Any mathematician will tell you, you can’t take 3 points on a graph and use that to predict a complicated trend. Similarly ask any scientist how to test for a specific correlation, and they’ll tell you change just one variable at a time, something these researchers also failed to do. If they were really trying to test the effects of carbs in the diet, they would have kept the ratios of protein : fat the same, but in each one it’s a different ratio. This alone makes the entire “study” a pointless waste, as you cannot work out what single factor might have caused the effect.
E.g. if only doing 3 tests as above, then something like this would have been significantly better as only 1 macro nutrient ratio changes:
- 70% carbs, 15% fat, 15% protein
- 40% carbs, 30% fat, 30% protein
- 10% carbs, 45% fat, 45% protein
Already it becomes more complicated however, as what do you do with total calories? Do you increase protein and fat as carbs reduce, in order to maintain a consistent calorie count? Or do you keep absolute calories of protein and fat constant, and let absolute calorie count reduce in line with the carb reduction? See, straight away you need to double the number of tests, and we haven’t even got to look at differing protein to fat ratios yet!
In the end, they should have done dozens of diets, of varying compositions. Not only looking at scientifically derived permutations as above, but also looking as specific commercial diets. (2) above happens to coincide with the Zone Diet proportions for example. Why not do Weight Watchers, Atkins, South Beach, Eskimo, Japanese, et al?
However, ignoring all that for the moment and assuming some actual value may be derived from this poor excuse for science. Let’s have a look at some of their findings. One key interesting point was:
“…the study also found that standard markers of cardiovascular risk, including cholesterol, were not changed in the animals fed the low-carb diet, despite the clear evidence of increased vascular disease.”
More evidence confirming that cholesterol does not in fact cause heart disease and the cholesterol hypothesis is a con, but I digress! It goes on to say:
“the usual markers thought to contribute to vascular disease, including the animals’ cholesterol and triglyceride levels, oxidative stress, insulin and glucose, as well as levels of some inflammatory cytokines… there was either no difference in measurements… or the numbers slightly favored the low-carb cohort,”
So they are saying that all the usual “well known” indicators of heart disease were either unchanged on the low carb diet, or better. Yet they have chosen to pick out the one indicator that went the other way, and highlighted that. Is this an example of that crazy saying that it’s the exception that proves the rule?!?
Basically there’s nothing to conclude from this little test. The test wasn’t big enough, wasn’t complete, wasn’t rigorous and wasn’t long enough to draw any conclusions. The fact that the classic markers were contradictory should be enough to show that. At the end of the day, what counts, and what is often missing from so called scientific studies (including most Statin research, but don’t get me started on those!) is the only measure that counts: actual mortality rates.
It is unforgivable for people to be warned off diets that conclusively make them thinner and healthier, because of a few weeks poor study of a few mice. Getting back to what really annoys me though, is the prat that the BBC rolled out to comment on it. He said:
“For now, it appears that a moderate and balanced diet, coupled with regular exercise, is probably best for most people.”
No shit Sherlock! The issue as ever, is what does “moderate and balanced” actually mean? Certainly it doesn’t mean what what Professor Alan Maryon-Davis, president, UK Faculty of Public Health, said:
“This research helps to back up the basic message that our diet should contain more starchy carbohydrate, not less”
My jaw hit the floor when I read that. You can’t draw that conclusion from this study at all. It’s a shameless example of someone using this doubtful study to spout his own personal agenda and draw wild conclusions from it. What these types fail to do, is define what they mean by “balanced”. Certainly in my book, balanced does not mean a diet where carbs out number protein and fat combined by 2:1, as the so called normal diet in this test was. How is that balanced? Muppets, they make me so cross!