Eating protein may help fight after-meal fatigue, study finds

We all know the feeling of an afternoon crash: eyes struggling to stay open, concentration drifting to thoughts of snuggling up in bed, and overall energy zapped. Sugar (glucose) may be the body’s main fuel for energy, but now a new study suggests that protein should be what we eat at lunch to help us stay awake and burn calories for the rest of the afternoon.

University of Cambridge researchers compared the effects of different nutrients on neurons in mouse brains. Wakefulness and calorie burning are dependent on secretion of a neuropeptide, orexin. When neurons don’t secrete enough orexin, sleepiness ensues—which can lead to fewer calories burned and more weight gained over time.

When the scientists measured the actions of protein (amino acids), carbohydrate (glucose), and fat (fatty acids) on the neurons, they found that the amino acids stimulated the cells to secrete orexin to a much greater extent than the other nutrients. In prior studies, the researchers found that orexin-secreting neurons are blocked by glucose. But, when interactions between glucose and protein were looked at in this study, the researchers found that protein prevents glucose from blocking the orexin secretion.

The results, published in the November issue of the journal Neuron, may help explain why people may feel particularly sleepy after eating meals rich in carbohydrates. Meals higher in protein and lower in total carbohydrates could help maintain alertness over the course of the day.

“What is exciting is to have a rational way to ‘tune’ select brain cells to be more or less active by deciding what food to eat,” said lead researcher Denis Burdakov in a University of Cambridge press release. “Not all brain cells are simply turned on by all nutrients, dietary composition is critical.”

“To combat obesity and insomnia in today’s society, we need more information on how diet affects sleep and appetite cells. For now, research suggests that if you have a choice between jam on toast, or egg whites on toast, go for the latter! Even though the two may contain the same number of calories, having a bit of protein will tell the body to burn more calories out of those consumed.”

Better yet, get your energizing dose of protein with IsaLean Shake, Bars, or Soups (and, for an even bigger protein boost, added IsaPro to your shake) at breakfast and lunch; and instead of an afternoon crash, you’ll be heading for an afternoon take-off. You’ll burn more calories too.

Reference: Karnani MM, Apergis-Schoute J, Adamantidis A et al. Activation of central orexin/hypocretin neurons by dietary amino acids. Neuron 2011;72:616-29. doi: 10.1016/j.neuron.2011.08.027