Personalizing Nutrition for an Active Lifestyle

By Daniel Heller, MSc, CSCS, RSCC

In the summer 2018, while exploring the Sequoia National Forest in California on mountain bikes, my friends and I experienced “hitting a wall” or a sudden lack of energy, where we felt like we couldn’t go any further. The physical symptoms we shared were different, but most could be linked back to our diets: weakness, nausea, headaches, cramps, and dizziness. Avoiding, or eliminating, these unwanted symptoms all comes down to making the right choices before, during, and after embarking on physical activities.

Fine-tuning one’s diet assumes the current diet is already diverse and complete with a variety of color, different types of proteins (plant and/or animal based), carbohydrates from whole grains, vegetables and fruits, and healthy fats. Now one could ask the question: “Am I consuming the right amounts of the correct foods to meet the demands of my activity?” This type of nutrition- and activity-focused thinking is called “activity-specific nutrition.” It encompasses the type, duration, intensity, and environment of the physical activity about to be embarked upon. Each of the factors that make up activity-specific nutrition play a role in determining what kind of sustenance our bodies need to prepare, sustain, and recover from the activity we intend to undertake.

Carbohydrates and proteins are the primary macronutrients utilized in physical activities that can be categorized into endurance and resistance training. For endurance-based activities (cycling, hiking, and running), carbohydrates provide sustained energy.¹ It should be noted that current research also suggests that fat can be used as an endurance fuel source.² For resistance training (weight lifting, circuit training, and manual labor), protein is critical in helping to repair and rebuild muscle.³

In a previous article three principles of strength and conditioning were discussed in detail. Now, we add an additional piece: What are good food choices that will support your favorite activities?

If you’re somewhere in the middle and usually participate in a high-intensity, interval training type of workout, you’ll have to consume enough protein to rebuild muscle and muscle fibers that undergo microtrauma from resistance training and replenish glycogen stores (energy) depleted from aerobic physical exertion.

The reality of caloric expenditure is that it varies based on age, body composition, and physical activity intensity. Many sports watches provide estimated caloric expenditure in real time. This makes it simple to assess under- or overconsumption of food as a whole. The number of calories consumed, and what are burned, needs to be in accordance with physical activity goals. For example, if your goal is to lose weight, you should be at a caloric deficit (eating 200-500 calories below what you’ve burned according to what your watch says). Fitness devices vary in price and features, but basic functions of measuring number of steps walked, calories burned, and heart rate are now commonly available on most of these devices.

There are, of course, caveats to the basic ideas for activity-specific nutrition presented here. For example, if you’re adhering to a ketogenic-style diet, the carbohydrate suggestion will not work. For ketogenic diets and endurance performance, I suggest reading Dr. Silverman’s article on why the keto diet may benefit athletes.

Until next time, live well and live active.