It is no secret that the saturated fats we often get from processed foods are not good for you. What does science conclude about what fats we should eat? Coming to a conclusive result on what fats are good for humans is quite difficult. These types of experiments and human observations have big variations and it is not simple to put a human in a cage where we can control other factors and only study the intake of different fats.
Our underlying genetics is a very important factor in this. The same type of fat intake can have a very different impact on different individuals. Having a high intake of saturated fats can have a very marked negative impact resulting in higher levels of “bad” cholesterol, LDL (Low-Density Lipoproteins)and heart disease for a part of the population, while it could have almost zero impact for others. Although we cannot predict this yet, in this case, family history may be an important indicator of your genetic background. A family history with a high number of cases with heart disease could be a sign that you need to think extra about avoiding saturated/trans fats.
Recently certain diets have popularized MCT (Medium-Chain Triglyceride) oil as “good” fats for you. These fats consist of shorter fat molecules that may be absorbed and metabolized easier than longer-chain fats. In particular, MCT oil is heavily encouraged in low carbohydrate ketogenic diets where a larger consumption of it promotes ketosis (the body forms ketones from fat for energy instead of using carbohydrates). There is no current credible scientific evidence to support beneficial health effects by MCT oils. It is important to note that MCT does not include essential fatty acids that humans need but could be a part of an otherwise balanced diet with a variety of unsaturated fats.
One of the few dietary components that we can be more certain of positive health effects is Omega-3 unsaturated fats that are enriched in fatty fish, nuts, and seeds. The latest large scale human studies indicate beneficial outcomes with a higher intake of these fats. A fair conclusion is that increasing or maintaining a high intake of Omega 3 unsaturated is fats is important no matter your background or current health status.