The aim of this review was to summarize the effect of high forage diets in relation heath promoting fatty acids. Fat content in the milk contributes mineral, vitamins, energy and essential fatty acids (C18:2n-6) and C18:3 n-3) to human. But, inclusion of high proportion milk and milk product especially, saturated fat in human diets is becoming questionable because of the health risk like obesity, cancer, diabetics, and cardiovascular disease. This creates negative altitude on consumers towards milk and milk product. Compromising the milk yield inclusion up to 70% of forage enhance n-3 PUFA and CLA (rumenic and vacinic acid). Studies in rat revealed that CLA (rumenic or vacenic acid) rich butter at 2% of its diet show reduction in mamary tumor and cholestrol indiuced coronary heart disease in rat. However, the contribution of the unsaturated fatty acid from milk to the total human diet is relatively low. Since for human to be effecteive it need reasonable to add 20% of its diet. Beside to this, the findings are still under animal model so further study is still needed to test its real effect on human health.