Based on clinical and nutritional data of VLCAD-deficient patients diagnosed before introduction of VLCAD deficiency in NBS [52], LCT restriction and MCT supplementation can be alleviated under normal circumstances in patients with >10% lcFAO as long as they follow strict dietary measures during illness and a maximum feeding pause in line with the guidelines that specify maximal fasting periods per age group [143]. This evidence concerns the gene ACADVL and very long chain acyl-CoA dehydrogenase deficiency.