Score a Point for Seth Roberts and the Shangri-La Diet

Earlier this week, we linked to a news article about a medical study finding that rats gained about the same amount of weight (80 grams, versus 72 grams on average) when they ate saccharine sweetened yogurt as when they ate yogurt sweetened with glucose. In both cases, the rats ate the yogurt in addition to their regular food.

If I understand the study’s conclusions, the researchers interpreted their results as evidence that the artificial sweeteners weakened the rats’ ability to make the link between sweet taste and calories. However, I don’t really see how this analysis works, because I doubt the rats’ regular food was sweet to begin with. So why would they eat more unsweetened food because of a destroyed link between sweetness and calories? I must be missing the point.

It seems to me that there is another explanation that fits perfectly with the findings of both this study and the theory underlying Seth Roberts‘s Shangri-La diet. As we wrote in a past Times column, Roberts bases his diet on the idea that, when you get your calories from sugar-laden foods, they provide a signal to your body to eat more, because the presence of sugar means that it must be a time of plenty. On the other hand, when your calories come from relatively tasteless food sources, they tell your body not to work too hard to obtain food, because your energy will be better spent waiting until the tasty stuff is available again. In this new experiment, adding the flavorful yogurt to the rats’ diets may have told both types of rats to eat all they could. Also, I would imagine that the artificially sweetened yogurt was even sweeter than the glucose flavored yogurt, in which case the signal to eat more was stronger for the saccharine-fed rats.

One thing I found peculiar about the study is that some of the rats refused to eat the yogurt, and consequently were excluded from the analysis. The study writeup lists every detail about the temperature of the room, and the schedule in which the lights were turned on and off; but, strangely enough, I couldn’t find any discussion of exactly how many rats refused to eat the yogurt. Given that the randomization was done based on which rats would get the different kind of yogurt, I would think that the researchers would want to report results for all the rats who were offered yogurt, not simply the ones who ate it.

And since when do rats refuse any type of human food? I always thought rats would eat anything. Charlotte’s Web apparently lied to me.