Numb the Sweet Tooth in Your Brain

Are you plagued by a sweet tooth that continually works against your weight loss efforts? Would you like to get rid of it, or at least weaken it some? A couple of recent studies brain fitness shed some light on this little devil in our heads that drives us to crave all those goodies.

It’s in Your Head

There is a part of your brain, called the pontine parabrachial nucleus (we’ll just call this the PBN from here on out) that is partly responsible for these cravings. The PBN sits in your brain stem, just above your spinal cord and plays a big role in sensing the foods you taste. It also sends messages to other parts of your brain involved in pleasure and in motor activity, to decide whether or not to keep your indulgences going.

Kovacs and Hajnal reported in the December 2008 issue of the Journal of Neurophysiology, that this little part of the brain may be different in obese individuals compared to normal weight folks. Actually they used an obese strain of rat and a related strain of healthy weight, but the message likely applies to humans as well. In fact, their study is consistent with an older study in humans, which we’ll get into in a minute.

What the new research found was that obese rats actually have fewer brain cells in the PBN that sense sugar. This means that the obese rats need more sugar to get the same level of sweet sensation, reminiscent of how drug addiction works. The more you use, the more you need, to get the same feeling.

Some older human studies showed something similar. In these, the researchers weren’t able to look into the human brains, but they did look at people who had successfully lost weight and others who had not been so successful. What they found was that the successful weight loss folks required less sugar to feel that a drink was pleasurably sweet. The folks that were less successful at losing weight required more sugar to get a pleasurable sweet sensation.

Numbing the Sweet Tooth

So the question is can we do anything about it? Can we change our PBN to sense pleasurable sweetness from less sugar, which would decrease our cravings for large doses of sweets on a regular basis? Well, there are several studies that suggest we can. If we slowly cut back on sugar, like weaning ourselves off a drug, we will become more sensitive and require less to feel satisfied.

Another new study actually shed some more light on this subject, again looking at the PBN. This study found that a class of brain chemicals, called endocannabinoids (which are what marijuana mimics) turn on our need for sugar and fat. Any child of the 60s will relate to the munchies.

DiPatrizio and Simansky reported in the September 2008 edition of the Journal of Neuroscience that rats given endocannabinoids straight into their PBN, ate more fat and sugar when given the chance, but did not eat more regular rat chow. Dosing up their PBN made them specifically want fat and sugar.

Why is this important? Several other studies suggest that a high omega-6 diet can increase the amount of endocannabinoids in your brain, which in turn might make you crave more fat and sugar. This may be a premature claim, but several studies (including some of our own) are beginning to point to a high omega-6 and low omega-3 diet as something that can crank up the drive to eat.

So another way to control your sweet tooth may be to reduce the amount of omega-6s you eat (which come from processed foods full of corn and vegetable oils) and crank up the amount of omega-3s you eat (which mostly come from fish). We’ve beat the omega-3 horse in several past articles so won’t cover it again here.

So this gives you two approaches to numbing down your sweet tooth. First, wean yourself off high doses of sugar, and, second, increase the ratio of omega-3s to omega-6s in your diet.

References:
Journal of Neurophysiology 2008, 100:2145-2157
Journal of Neuroscience 2008, 28(39):9702-9709