Most of us have experienced that time of day when our energy level dips, our concentration wanes and we're ready to take a nap – triggers that cause some people to reach for a sugary snack.
But if you had a choice between a chocolate bar and handful of almonds, new research findings suggest you're better off choosing the nuts to feel more energetic.
According to the report, published this month in the journal Neuron, protein – not sugar – stimulates certain brain cells into keeping us alert. What's more, protein-rich foods can also activate these brain cells to tell the body to use up energy stores, a consequence that can help us stay slim.
It's known that orexin cells in the brain release a specific chemical which stimulates wakefulness and regulates energy balance.
Previous research has shown that glucose (sugar) blocks the activity of orexin cells, which may be the cause of feeling sluggish after meals.
The current study set out to determine if certain nutrients influenced those chemical signals. The researchers gave mice mixtures of amino acids – the building blocks of protein – which were similar in composition to egg white.
They discovered that the amino acid mixture prevented glucose from blocking orexin cell activity. In other words, eating protein at meals may counteract after-meal drowsiness brought on by sugar or carbohydrate.
These findings help explain what other studies have found: After eating a high-protein versus a high-carbohydrate meal, people feel more alert.
The researchers concluded that it's the balance of nutrients you consume at a meal – not the total number of calories – that influences whether you'll feel sleepy or alert. Even though two meals may contain the same number of calories, the one that includes protein will make you feel more energetic and tell your body to burn more of those calories.
While ensuring your meals and snacks offer protein may help you fend off that afternoon energy slump, other dietary adjustments can help too. Blunders such as skipping meals, running low on water and drinking too much coffee can leave you feeling drained by midafternoon.
Divide your protein intake among three meals and snacks. At meals, choose lean versions of protein such as lean meat, fish, poultry, egg whites, tofu, beans or lentils.
Protein-rich snack choices include nuts, soy nuts, edamame, hard-boiled eggs, part skim cheese, yogurt (Greek yogurt is higher in protein than regular), and unflavoured soy beverages.
Choose low GI carbs
Your body requires carbohydrates for energy. They're metabolized into blood glucose, the only form of energy that the body can use immediately. Carbohydrate stores (glycogen) in your liver is used to replenish blood glucose, while the stores in your muscle fuels exercise.
Low glycemic carbohydrates are digested and converted to blood glucose slowly. As a result, the body gets a balanced release of energy rather that a quick burst.
Such slow-burning carbohydrates include dense, grainy breads, bran cereals, steel-cut and large-flake oatmeal, milk, yogurt, soy beverages, apples, pears, oranges, dried apricots, berries, nuts, seeds, beans and lentils.
Studies show that eating the morning meal improves mood, memory, and feelings of energy in adults and kids.
Breakfasts that deliver protein and low glycemic carbohydrate include bran cereal with milk, fruit and nuts; steel-cut oatmeal topped with Greek yogurt; a smoothie made with milk (or soy milk), berries and ground flax; and whole grain toast with egg whites and fruit salad.
Plan midday snacks
To prevent your energy level from fading, go no longer than three hours without eating.
Snacks should boost your blood sugar and keep it relatively stable until mealtime – think carbohydrate (low glycemic) and protein. Try fruit and nuts, a decaf latte (or yogurt) and a piece of fruit, bean soup, whole grain crackers (Wasa, Ryvita and FinnCrisp are low glycemic) and part skim cheese.
Energy bars can also be used for snacks. Choose bars that contain 20 to 25 grams of carbohydrate and 10 to 18 grams of protein. Look for products made from whole food ingredients that limit refined sugars (e.g. Elevate Me!, Vega Energy Bars, the Simply Bar, Larabar).
If you're concerned about weight gain, keep snacks to 150 to 200 calories (women) and 200 to 250 calories (men).
Water in your bloodstream circulates oxygen and nutrients to your tissues, removes wastes and is an essential ingredient in the production of energy molecules.
Men need to drink 12 cups (3 litres) of water each day; women need 9 cups (2.2 litres). With the exception of alcoholic beverages, all fluids count toward meeting water requirements. That includes water, milk, unsweetened juices, even tea and coffee.
Caffeine might perk you up during the day but it can also keep you awake at night, particularly if consumed late in the afternoon. Caffeine can disrupt sleep by blocking the body's production of adenosine, a brain chemical that causes drowsiness by slowing down nerve cell activity.
Women of childbearing age should limit caffeine intake to 300 milligrams per day; other healthy adults should consume no more than 400 milligrams daily. (One eight-ounce cup of regular coffee has roughly 180 mg of caffeine.)
If you feel you consume too much caffeine, gradually cut back over three weeks to avoid withdrawal symptoms such as headache and muscle soreness.
Meet iron requirements
An iron deficiency, even without anemia, can cause fatigue, lethargy and difficulty concentrating.
Iron-rich foods include beef, oysters, clams, turkey, chicken, tuna, pork loin and halibut, ready-to-eat breakfast cereal, soybeans, lentils, baked beans, black beans, firm tofu, cooked spinach, raisins and prune juice.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Her website is lesliebeck.com.