Macro partitioning

Eucaloric diets that are very low in fat and high in simple sugars markedly stimulate de novo fatty acid synthesis, leading to increased plasma triglycerides proportional to the amount of synthesis.

If you eat a diet that is very low in fat and high in simple sugars (like high sugar/starch ratios), your body will synthesize more fat from those carbohydrates, which raises your blood triglycerides. This happens regardless of whether you are lean or obese, and it is not driven by your insulin levels. To manage triglycerides, avoid extreme low-fat diets that are high in simple sugars.