Fat: Innocent Until Proven Guilty

Low-fat milk. Zero grams saturated fat. Fat-free! A quick scan of the food products in a grocery store will reveal a peculiar theme: boasting fat-deficiency. These items are often more popular among consumers, as a survey conducted by Food Insight found: one out of three people prefer to buy only reduced fat foods, while only one out of 10 seeks out full fat foods. A frequently cited reason for low-fat products’ popularity is the pre-conceived notion that they are healthier than full fat products. Specifically, many believe that excess fat intake will predispose them to health conditions like heart disease and obesity. While this narrative may have its foundations in early published research, it doesn’t illustrate the nuanced truth with scientific accuracy. 

Fat first came under scrutiny in the 1950s and ‘60s, when it was investigated as a major cause of heart disease. In 1953, Ancel Keys, a prominent researcher and dietitian of the time, introduced cholesterol as an indicator of cardiovascular disease. In his Seven Countries Study, he and a team of researchers found that high fat intake was a strong predictor of heart attacks later in life. Keys’s study proved only that there was some potential link between certain types of fat—such as cholesterol—and heart disease. Soon after his initial study, subsequent clinical trials around the world published findings that seemed to strengthen his hypothesis. Finally, in 1977, the U.S. federal government released a new recommended health plan, titled Dietary Goals for the United States, that officially endorsed a fat-free diet. The guideline greatly influenced public school nutrition plans and health curriculums, medical practitioners’ advice, and the beliefs of the general American public for the next two decades.

The relationship between fat and heart disease, however, proved to be much more complex than what Keys and assenters made it out to be. For example, more recent research has revealed that though cardiovascular disease is indeed linked to fat consumption, sugar also plays a sizable role. A 2014 study published in JAMA Internal Medicine found that those who got more than 25 percent of their daily calories from sugar were twice as likely to die from heart disease than those that got less than 10 percent of their daily calories from sugar. Even so, complications from overconsumption of sugar were largely ignored during the anti-fat era. In a turn of events, a 2016 exposé published by Dr. Cristin Kearns of the University of California, San Francisco uncovered documents revealing that a group called the Sugar Research Association had paid Harvard researchers $50,000 to explore the relationship between sugar, fat, and cardiovascular disease. The association cherry-picked the studies published by the researchers. The selected studies tended to link fat consumption—rather than sugar consumption—more closely to heart disease. The group, self-characterized as “the scientific voice of the U.S. sugar industry,” stood to gain profits and market share from shifting blame for increased risk of cardiovascular disease from sugar to fat. 

In reality, there is evidence to show that cutting back on fat does not have any consistently notable benefit for heart health. In 2021, a study published in Nutrition & Metabolism examined 2,809 adults over a range of 10 to 11 years and found no strong connection between fat consumption—specifically of saturated fats—and cardiovascular disease. The paper concluded by encouraging scientists to reevaluate the importance of a low-fat diet. 

The original biased studies and the resulting demonization of fat are extremely dangerous for the population because they inaccurately represent the health risks of different products. Suggesting that fat directly leads to poor health is problematic in numerous ways. For one, it implies a strict cause and effect relationship between the two. Americans, under the influence of this idea, began to favor products with less fat. A good example is milk, which was re-released in low-fat and no-fat versions marketed as healthier alternatives. However, a global analysis conducted by Dr. Andrew Mente and his team suggested that including whole fat dairy in a balanced diet of fruits, vegetables, nuts, and lean meat is very beneficial for heart health. Discrepancies in the research also suggest a second problem with the low-fat fad: there is no one-size-fits-all in the nutritional sciences. A healthy diet will naturally differ from person to person; lifestyle and biological factors—such as genetic predisposal to cardiovascular issues, excessive smoking, and being overweight—always play a role. 

Non-fat products remain pervasive in nutritional guidelines today despite their impact on health being called into question. Americans may choose to continue buying them, but they should consider a holistic approach to their diet. Regardless, inquiry into new diets and popular health tips remains relevant—the public frenzy surrounding the anti-fat agenda in the ‘60s is ominously reminiscent of today’s newest onslaught of nutritional advice.