If you have a big waistline is your brain smaller?

Posted on Wed, 4 Aug 10

It is now normal to be overweight with most people in the western world being either overweight or obese. A serious consequence of an expanding waistline is a shrinking brain.

Obesity is associated with poor mental performance and function and accelerated brain aging, symptoms of which can be apparent even when you are relatively young. For example, a study of otherwise healthy adults between the ages of 21-82 found that obesity was associated with poorer memory performance independent of age (1). A likely reason for this discovery is that being overweight destroys your brain.

Big bodies, skinny brains  

Using brain imaging technology a number of recent investigations have found that as your weight increases, your brain shrinks. Compared with people who have a healthy Body Mass Index (BMI) of 18.5-25 those who are overweight (BMI: 25-30) or obese (BMI > 30) have signs of atrophy in several regions of the brain and an overall smaller brain size (2-4).

Grow your brain back

Fortunately there is evidence to suggest that a broken brain can be repaired. The same processes that lead to brain breakdown in those who are overweight could be reversed with dietary and lifestyle change and the human brain possesses a remarkable ability to regenerate and repair itself (5-6).

Being overweight, along with a smaller brain size, may simply be symptoms of greater problem. The reasons we become overweight may be the same reasons our brain breaks down. Healthy behaviours linked to better weight management such as regular exercise, stress management and a healthy diet are also associated with better mental health, and a bigger brain (7-11).

References

1. Gunstad J, Paul RH, Cohen RA, Tate DF, Gordon E. Obesity is associated with memory deficits in young and middle-aged adults. Eat Weight Disord. 2006 Mar;11(1):e15-9.

2. Raji CA, et al. Brain structure and obesity. Hum Brain Mapp. 2010 Mar;31(3):353-64.

3. Gunstad J, et al. Relationship between body mass index and brain volume in healthy adults. Int J Neurosci. 2008 Nov;118(11):1582-93.

4. Ward MA, et al. The effect of body mass index on global brain volume in middle-aged adults: a cross sectional study. BMC Neurol. 2005 Dec 2;5:23.

5. Reagan LP, et al. The As and Ds of stress: metabolic, morphological and behavioral consequences. Eur J Pharmacol. 2008 May 6; 585(1): 64–75

6. Cirulli F, Alleva E. The NGF saga: from animal models of psychosocial stress to stress-related psychopathology. Front Neuroendocrinol. 2009 Aug;30(3):379-95.

7. Erickson KI, et al. Aerobic fitness is associated with hippocampal volume in elderly humans. Hippocampus 2009;19:1030–1039.

8. Lazar SW, et al. Meditation experience is associated with increased cortical thickness. NeuroReport 2005;16:1893–1897.

9. de Lange FP, et al. Increase in prefrontal cortical volume following cognitive behavioural therapy in patients with chronic fatigue syndrome. Brain 2008;131:2172–2180.

10. Gómez-Pinilla F. Brain foods: the effects of nutrients on brain function. Nat Rev Neurosci. 2008 Jul;9(7):568-78.

11. Stranahan AM, et al. Diet-induced insulin resistance impairs hippocampal synaptic plasticity and cognition in middle-aged rats. Hippocampus. 2008;18(11):1085-8.