Fat Body = Not Fat Head?

A new study finds obese people have 8 percent less brain tissue than normal-weight individuals. Their brains look 16 years older than the brains of lean individuals, researchers said today.

Those classified as overweight have 4 percent less brain tissue and their brains appear to have aged prematurely by 8 years

I don’t know what to think about this yet. It would be nice to know more about the proximate mechanisms. I’m guessing this is a cardio-vascular thing.


hat tip: Natalie.


  1. #1 sailor
    August 26, 2009

    Scary eh?

    There has been some research recently that when cells are mildly stressed (ie by starving a day a week) they stay healthier and reproduce better. Could this in any way be a sort of converse?

  2. #2 Jared
    August 26, 2009

    Actually, it’s looking like high-fat diets lead to neurological inflammation in the brain which results in low oxygen and nerve death. This is actually being investigated by Dr. Morrison at Pennington Biomedical in Baton Rouge.

  3. #3 sailor
    August 26, 2009

    Thanks for the info.

  4. #4 ebohlman
    August 27, 2009

    Did they control for height? Remember that obesity/overweight is determined by BMI, which is linearly proportional to weight and quadratically inversely proportional to height. Therefore, a small difference in height between two people of the same weight will result in a much bigger difference in BMI than a small difference in weight between two people of the same height. We tend to ignore the influence of height on BMI because it’s not a factor that an adult can control, but it’s still present.

    So if there’s a positive correlation between height and brain mass (and I vaguely recall that there is, probably influenced by nutrition in childhood), then you could see a negative correlation between BMI and brain mass.

  5. #5 Wayne Robinson
    August 27, 2009

    Could it be related to obstructive sleep apnoea? Sleep apnoea is increased in the obese and overweight, and perhaps the periodic anoxia at night might affect brain cell survival.

  6. #6 catgirl
    August 27, 2009

    This study is interesting, and I wish I still had access to journals to read the actual study. However, the study involved 94 people in their 70s, so I’m careful about jumping to conclusions for the rest of the population. The direction of causation is not clear. Some of the regions affected involve memory, planning, and sensory processing, which could possibly make those people more prone to overeating. I’d like to see the study repeated in a larger group of people from all age groups, and I’d also like to see a longitudinal study to see what affect gaining or losing weight has on brain size.

  7. #7 mathyoo
    August 27, 2009

    And is it reversible? If an obese person changes their lifestyle and achieves a healthy weight, does the brain adjust?

  8. #8 Jared
    August 27, 2009

    Mathyoo, according to the research I’ve seen in animal models, no. The good news is that getting to that healthy weight stops further degeneration.

    Another fun study:

  9. #9 mathyoo
    August 27, 2009

    Damn, I guess I better get serous about dropping weight and keeping it off, then!

  10. #10 Jared
    August 27, 2009

    Try not to be “serious as a heart attack” about it, though…