Doctor's Orders: Complexity
Complex carbs are constructed of long chains of sugars. Most, but not all, complex carbs are low-glycemic or slow digesting. For most meals, stress whole-grain products (whole-wheat bread and pastas, oatmeal, brown rice, etc.) and sweet potatoes, which are all slow digesting, as opposed to white breads, white potatoes and refined sugars, which are all fast digesting.
Slow-digesting carbs provide longer-lasting energy, and there's less chance they'll be stored as body fat. During a mass-building phase, strive to take in roughly 2g of carbohydrates per body pound on your workout days. If you're not growing as quickly as you'd like or find yourself unnaturally fatigued during a workout, you can slowly up your carbs.
As critical as protein is for building muscle, carbs are also important when you're trying to maximize muscle growth. The carbs you consume get stored in your muscles as glycogen. Glycogen pulls lots of water into the muscle, which fills the muscle cells. This makes your muscle bellies look fuller, but not just in the short run. When you fill a muscle with fluid, it places a stretch on the muscle membrane, which instigates pathways that lead to an increase in muscle protein synthesis. So carb up when mass is your main goal!
Today, many people worry about consuming wheat due to the gluten it contains. Gluten is a type of protein to which many people are sensitive. If your stomach is sensitive to gluten, avoid eating whole-wheat bread, pastas, crackers, etc. Watch out for some oat-based cereals, too, as they may also contain wheat. Today, there are many glute- free food options, but naturally gluten-free and low-glycemic carb sources are even better. These include sweet potatoes, oatmeal, quinoa, and fruit.
Remember that every rest day should be an active rest day. Rest days are for recovery; they're not an excuse to be lazy. Get out and hit 15-30 minutes of HIIT cardio today, or perform 30-60 minutes of your favorite activity: hiking, biking, walking, playing a sport, etc.