Triacylglyceride
Triglycerides are made of three fatty acids connected to a glycerol. The long, repeating chain of carbons and hydrogens at the end of the fatty acid, called the fatty acid "tail", makes the molecule hydrophobic, meaning it does not mix with water. These hydrophobic tails are why oil and water do not mix. The longer the fatty acid tail length, the more energy the triglyceride has.