This study will treat children and adults who have documented deficiencies of mitochondrial fatty acid oxidation including disorders of the following enzymes: Carnitine-Acylcarnitine Translocase (CATR), Carnitine Palmitoyltransferase I and II (CPT I, CPT II), Very-Long Chain Acyl-CoA dehydrogenase (VLCAD), L-3-Hydroxy-Acyl-CoA Dehydrogenase (LCHAD), Acyl-CoA Dehydrogenase type 9 (ACAD9) and Mitochondrial Trifunctional Protein (TFP) with triheptanoin oil. This study is also open to patients with any type of glycogen storage disease, pyruvate carboxylase deficiency, type B, or Barth Syndrome.