There are a few key symptoms to watch out for when it comes to high fructose corn syrup. First, pay attention to how much sugar you're consuming on a daily basis. If you find that you're eating more processed foods and sugary snacks than usual, this could be a sign that your body is trying to metabolize high fructose corn syrup. Also, keep an eye out for changes in your weight. If you start gaining weight without changing your diet or lifestyle, this could be another symptom of high fructose corn syrup metabolism. Lastly, watch for fatigue or lethargy. If you find yourself feeling tired all the time, even after getting a good night's sleep, this could be another sign that your body is having trouble dealing with high fructose corn syrup.