How are MY FOODBOOK and fatigue related?

The provided context does not contain any direct information about 'MY FOODBOOK' or its relation to fatigue. It only mentions general DNA-based diet tests, with evidence rated as 'marketing'. Without specific studies or product details, no scientifically sound conclusion can be drawn. Fatigue has many causes (sleep, stress, nutrient deficiencies, medical conditions) that a simple test cannot address. Be cautious of exaggerated claims.