It’s often been said that you are what you eat--but might that not also imply that your diet can affect your mood and the alertness of your mind too?
Well, a new animal study published in the journal Neuron suggests that, depending on when you eat them, carbohydrates (in the form of glucose) and proteins (as amino acids) do significantly affect not only your level of wakefulness, but also how peppy your metabolism is.
Researchers from the University of Cambridge, U.K., were studying the levels of a substance called orexin in the brains of rats to find out what happened to this chemical when the animals ate either carbohydrates or proteins at different times. Orexins are neuropeptide hormones--stimulant chemicals--that strongly excite the parts of the brain that encourage increased wakefulness and a faster metabolism.
These researchers knew from past studies that carbohydrates in the form of glucose decrease orexin levels and lead to lower metabolism and gains in weight. But these U.K. scientists now have discovered that protein acts in the opposite way: It stimulates orexins, resulting in greater energy use and the loss of weight.
The scientists found that whenever the rats ate protein in the form of amino acids, orexins got busy stimulating the alertness centers in the rats' brains, with the result that the animals used up more energy. The scientists also found that glucose had the opposite effect from proteins on this "wakefulness hormone" (orexin): The carbs blocked the hormone's stimulating action.
But the most important discovery the U.K. researchers made was this: When the body is digesting protein, that protein was somehow able to prevent glucose from blocking orexin's beneficial actions.
The study authors concluded that protein in a meal might be helping to keep us alert and telling our bodies to burn more of the calories we ingest. So, perhaps protein will one day play an additional role in our diets--to help us stay awake during the day, and even to assist in weight loss.
Although this study was performed on animals, its results suggest that we might be able to boost our metabolisms and become more alert by adjusting the composition of our diets.
A few other research studies in the past have alluded to this topic. For example, earlier results suggested that "weight-friendly hormones" like peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) could reduce appetite and contribute to a feeling of fullness after meals. PYY and GLP-1 are produced in the gut when we eat protein-rich foods, and the more weight we lose, the more sensitive our brains become to these hormones.
For several reasons (one of which is this new finding that protein can stimulate weight-friendly hormones), I now suggest to my patients that they include some protein with every meal and snack they eat, and that they aim not to go for more than 5 hours without ingesting some food, so as to keep the nervous system from sending "starvation signals" to the brain.
Breakfast. If this is not your favorite meal, or if you skip it regularly, consider a high-quality protein shake made with whey protein isolate. (If you’re a vegetarian, soy protein isolate or hemp protein can furnish protein that's almost as high in quality.) Try adding fresh or frozen fruit to the shake for fiber, along with some “good carbs,” such as old-fashioned oatmeal flakes. Or, if you’re not terribly alert in the a.m., or you don’t have much time to whip something up, consider a pre-mixed shake.
Lunch. If you’re a “grab'n'go” type of person at lunchtime, consider some of the ready-made lunches you can find at the market, including tofu-to-go, or canned tuna- and chicken-to-go, which are usually found near the canned tuna section in little disposable baggies.
Dinner. Of course, home-cooked meals are ideal, but if that’s not possible, you might even want to try one of the healthy pre-prepared meals found online, such as Diet-to-Go, DineWise, eDiets, or Healthy Chef Creations. Some of these meals these companies produce are fairly inexpensive and come in vegetarian and gluten-free alternatives that include plenty of protein. Otherwise, try cooking some meals on your days off and freezing them.
Nutritional experts say that the “average” healthy adult needs between 60 grams and 80 grams of protein per day or a portion of protein at both lunch and dinner that's about the size of a computer mouse or a deck of cards (about 21 grams at each meal). At breakfast, try for at least half that amount of protein.
Also include some protein in your snacks, if you eat those. Include such things as Greek yogurt (or soy yogurt, if you’re vegetarian), string cheese (or soy), edamame (in the frozen section), and skim or 1-percent milk (or soy or hemp milk).