There is nothing stopping you from being active or competing in a sport of your choice. A sedentary lifestyle can be harmful to your health, so physical activity is encouraged wherever possible and through all life stages, not just your teenage years.
Active people burn more energy (calories) than people who are not active. If you do not consume enough energy from your low protein diet and protein substitutes, then the body breaks down its protein stores from the muscles to use for energy. This breakdown of protein releases phe into the blood causing phe levels to increase. The type, intensity and length of time exercising will determine how much energy and protein you require. Taking your protein substitute as prescribed should provide your body with enough protein to stop protein in muscles being broken down.
You might want to consider the timings of your protein substitute if you exercise on a regular basis or compete in sports. Your protein substitute contains the “building blocks” for muscle and it might be better to take this following an intense gym session, endurance event or a match. Combining your protein substitute with a carbohydrate based meal such as low protein rice or pasta can aid recovery.
‘Protein powders’ that some people use to increase muscle mass are not appropriate for a person with PKU as they will increase blood phe levels. If you compete competitively, your protein and energy (calorie) demands might be higher than the average person. Your metabolic team can help you to ensure you are eating enough food for your energy demands and meeting your protein needs from diet and your protein substitute, so you can achieve your activity goals, whilst staying on top of your phe levels.
If you’re new to exercise, aiming for a minimum of 10,000 steps per day is a good start and as an added bonus, it’s free! You can achieve this by getting off the bus one stop early, going for a walk after school or college, scheduling in a regular walk with a friend or family member and making a conscious effort to stand up and walk somewhere at least once an hour.