Pre-Workout and Post-Workout Fueling


By, Tiffany Batsakis – O2X On-Site Specialist


Proper fueling for pre-workout and post workout improves exercise performance, optimizes body composition, and helps restore glycogen so that energy is available for the next bout of activity, whether it’s in the gym, a busy day on the job, or training in the field. What foods are best before, what do we need after, what’s the difference, and what happens if we don’t choose quality or even too much fuel?


When it comes to energy availability, carbohydrates are the key. The muscles and the brain both utilize carbohydrates as a source of fuel, so providing these organs with the appropriate types and amounts are critical to perform optimally. Nutrient timing is also important so we will look at some recommendations for the day. 


Generally speaking, to optimize body composition and increase lean body mass, adequate protein intake is beneficial. I generally recommend 1.2-2.2 grams of protein/kg of body weight over the course of the day, with 1.6 grams being a good, middle of the road recommendation. To get body weight in kilograms, divide your weight by 2.2. For example, a person who weighs 200 pounds/2.2 = 90 kilograms. Multiply by 1.2 and 2.2 to get a range of 110 to 200 grams of protein/d. Adequate protein intake will help you not only maintain existing muscle mass, but build new muscle as well. Leucine is a key amino acid when it comes to muscle protein synthesis and post exercise, as it contributes to muscle repair and building. We find leucine in dairy products, whey protein powder, chicken, fish, and other animal based sources of protein. A common recommendation is to get about 25-30 grams of protein post workout. Most commercially available protein supplements provide 20-30 grams of protein and 4 ounces of animal based protein generally provides about 25 grams of this macronutrient. Results from a study conducted in 2017, however, showed both pre- and post-workout protein intake had similar effects, so in reality, as long as you consume protein around your workout time, you can benefit.


For exercise and physical activity, the amount and type of carbohydrate should be based on the type and duration of the activity. Needs will of course vary from person to person and the timing of this macronutrient before training is important. Carbohydrate recommendations range from 3-12 grams of carbohydrate/kg body weight/day. On days when you are less active, it is recommended to have fewer carbohydrates, and on days when you are more active, more are beneficial. Aim for 1 to 4 grams of CHO within 4 hours of training and about 25-30 grams within an hour of your activity. Again, this number can vary based on activity duration. A good recommendation is to try different fueling strategies over time and slowly increase carbohydrate intake until you find an amount that suits and fuels you. For example, on a long bike ride (>25 miles), I like to eat 75 grams CHO about 30 minutes before I head out and 30-60 grams every 1.5 hours thereafter. Oftentimes, around the 50 mile mark, I begin eating glucose gummies every few miles to keep carbohydrates available for fuel. 


Here are some guidelines based on the type of activity:


Type Of Activity

Activity Example 

Carbohydrate Recommendations 

Low intensity or skill type activities

Gym training session, baseball

3-5 g/kg body weight/d

Moderate, ~1 hour/d

Jogging, biking, burn training

5-7 g/kg body weight/d

Endurance, ~1-3 hrs/d, moderate to high intensity

Running, cycling

6-10 g/kg body weight/d

>4 hours, moderate to high intensity

Hiking, cycling, long training day

8-12 g/kg body weight/d


Inadequate carbohydrate intake before a workout can result in low energy or a feeling of lethargy, while too much food can cause GI upset. Blood flow to the gut increases after meals which may cause some people to feel drowsy. Additionally, carbohydrates increase serotonin levels, a neurotransmitter sometimes called the “happy hormone,” and can help people feel more calm. The key is to find the right amount and types of carbs that fuel you best, and avoid adopting a new fueling strategy before a game or an important training day. 


Some carbs that provide a good boost of fuel and digest easily are fruit like bananas, oatmeal and various oat/granola bars. Dates provide a nearly equal amount of both glucose and fructose, which are metabolized in different pathways, allowing more energy to get into the cell when needed. Some athletes prefer gels and blocks when it comes to endurance events and sports drinks with different added sugars and electrolytes can be good options, especially if you don’t have time to stop and eat during your activity. 


Fueling both pre- and post-workout is important to help repair, replenish, and restore, so choose nutritious foods that provides both protein and carbs. You can take what time of day you are training and mealtimes into consideration as well. For example, if you workout late in the morning, a post-workout protein shake blended with a banana is a great option, however, if you finish your workout just before lunch time, a quality meal of lean protein with some carbohydrates and vegetables would be appropriate at this time.


For more pre- and post-workout snack ideas, please see the attached handouts. While we did provide some recommendations for carbohydrate intake, each individual is different, so finding your unique fueling strategy is recommended. 


Carbohydrate Recommendations for Athletes 

Pre- Versus Post-Workout Exercise Protein Intake Has Similar Effects On Muscular Adaptations

Carbohydrate Recommendations For Athletes 

Carb Mixes and Benefits 

Nutrition and Athletic Performance


About O2X On-Site Human Performance Specialist Tiffany Batsakis:

Tiffany Batsakis is an O2X On-Site Nutrition Specialist and Registered Dietitian. Her background includes working with tactical athletes and a focus on health and wellness. Tiffany provides services such as meal plans, nutrition analysis, and education. She is passionate about behavior change and stays informed on the latest nutrition developments. Her dedication and expertise make her a valuable resource for improving nutrition outcomes.


About O2X Human Performance:    


O2X Human Performance provides comprehensive, science-backed programs to hundreds of public safety departments, federal agencies, and the military. O2X works with clients to elevate culture, improve mental and physical well-being, support healthy lifestyles, and reduce healthcare costs associated with injuries and illnesses. Driven by results and cutting-edge research, O2X programs are designed and delivered by a team of Special Operations veterans, high-level athletes, and hundreds of leading experts in their respective fields of human performance