Less Food=More Memory?
By Gregory Kellett, a cognitive neuroscience researcher at SFSU and science writer for Lumos Labs .
Data collected by Agnes Flöel and her crew at the University of Munster in Germany seems to give yet another reason to resist that second helping of chocolate cake.
The research compared short-term memory performance of overweight individuals who reduced their caloric intake by 30% over 3 months with individuals who maintained their regular diet over the same 3 months.
Results:
- After 3 months, those on the decreased calorie diet improved by 20% on short-term memory tests of word recall.
- Participants who did not change their caloric intake showed no improvements.
The study coincides with multiple other studies demonstrating improved brain plasticity in animals fed calorie restricted diets. Some possible mechanisms at work include:
- The modified action of neurotransmitters
- The stimulation of neurogenesis (production of neurons)
- Increases in cell metabolism
However, in the above study, there may be other factors at work. As all the participants were overweight to begin with, the improvements could simply be due to an increase in overall health (IE blood flow, increased oxygen etc). Studies “starving” healthy individuals seem to be called for in order to eliminate this possibility.
References:
Caloric restriction improves memory in elderly humans. (2009, January 26). . Retrieved January 27, 2009, from http://www.pnas.org/content/early/2009/01/26/0808587106.
Fontán-Lozano, A., Sáez-Cassanelli, J. L., Inda, M. C., de los Santos-Arteaga, M., Sierra-Domínguez, S. A., López-Lluch, G., et al. (2007). Caloric restriction increases learning consolidation and facilitates synaptic plasticity through mechanisms dependent on NR2B subunits of the NMDA receptor. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 27(38), 10185-95. doi: 10.1523/JNEUROSCI.2757-07.2007.
Stranahan, A., & Mattson, M. (2008). Impact of Energy Intake and Expenditure on Neuronal Plasticity. Neuromolecular Medicine.
Jan 27, 2009
These studies are too general.
The improved performance could be due to a decrease in carbohydrate consumption.
The modern high-carb low-fat diet is completely backward from an evolutionary perspective.
A high-carb diet soaks the brain in glucose and insulin, causing insulin resistance (and thus poor glucose metabolism), as well as abnormally high serotonin levels (resulting in, yes, serotonin resistance), among other neurotransmitter imbalances (e.g. dopamine).
Glucose metabolism and a healthy serotonin and dopamine system are critical for memory and mental energy. I really wonder how much of the improvement was from calorie restriction, and how much was from glucose (i.e. carbohydrate) restriction.
Jan 27, 2009
Excellent point. That is yet another factor that could be at play here. The study details are still in press and not yet available on pubmed,…but it would be interesting to see if they specify what types of calories were restricted.
Feb 15, 2009
Sigh. And the cake looks so amazing. Just one bite???
Feb 23, 2009
One concept that I’ve seen in brain training is that it is often the differences in activity that produces changes.
If you compare the brain study to basic muscle flexibility which is a similar physical system, the less fat people seem more flexible because they havent got as much fat about them stopping them moving and they tend to do more also because they havent got as much of a “gut full” feeling. More activity generally means more plastic.
If that person holds the slice of cake back there’s generally more activity and opportunity for physical and brain activity rather than sitting munching.
Oct 21, 2009
Those counterpoints make sense, and the study is still pending. But it does make sense to me. Before I even started Lumosity, people were amazed at my ability to remember things in both the short-term and long-term and would always use me as a walking post-it note. I maintain a very healthy lifestyle, and one of the things I do is eat only once a day and avoid all sweets. (But I do admit that the one meal that I do eat at night is huge.)