If you want to know what caused the obesity epidemic, here it is!
Sugar, Salt, Fat is about how the processed food industry figured out how to use sugar, salt, and fat to make processed foods taste more than just good, but to make them something close to addictive. With this technology, they could make cheap, unnutritious foods taste good, and use the resulting high margins to fund advertising to drive demand. The food industry also made these foods more convenient than cooking. They even played a role in killing off home economics in the schools to ensure the next generation would not know how to cook.
Oh, one little side-effect that the industry needs to sweep under the rug: because these processed foods are so unlike foods found in nature, the body body can't properly gauge when these foods make the body full -- causing people to consume far more calories than they need.
Some interesting angles to the story are the involvement of the tobacco industry, such as Phillip Morris’s acquisition of food companies; and the healthy lifestyles pursued by the food industry executives, who eat their own products far more sparingly than the general public does.
This is not rocket science, but it’s great investigative journalism. It may be the best investigative journalism about the food industry since Upton Sinclair's work a century ago about food impurities. Yes, that good; that important.
One minor annoyance is that the narrator, Scott Brick, over dramatizes. Brick mostly narrates fiction, which he should probably stick to. He was perhaps chosen because he did an excellent narration of The Omnivore’s Dilemma (another great book for folks concerned about modern food), but that book was more of a memoir, making it a better fit with his narration style. Sugar, Salt, Fat is pure investigative journalism. The emotional level of Brick’s reading doesn’t fit with this genre.