In a new book, a metabolic coach says to beware of ‘low-fat’ foods, many of which contain sugar

As if the physical changes to our food and lifestyle weren’t challenging enough, our understanding of nutrition has been clouded by a series of misconceptions – myths that have steered us further from metabolic health while seemingly promising to lead us toward it.

While our food and lifestyle have transformed dramatically, the very systems meant to warn us – nutrition education, food labeling, and health guidelines – have been compromised by marketing influences and outdated science. Several widespread nutrition myths have become so embedded in our culture that they actively prevent us from addressing the underlying metabolic problems.

The first and most damaging of these was the low-fat craze. In the 1960s, when heart disease was rising, the American Heart Association made a bold move. Based on research linking saturated fat to heart problems, they recommended that everyone cut down on total fat. This kicked off decades of fat-phobia that influences how many people eat today.

This fear of fat fundamentally changed our food landscape. Food manufacturers, initially concerned about making reduced-fat products palatable, discovered they could replace fat with sugar. Throughout the 1980s and 1990s, grocery shelves were filled with “low-fat” products marketed as healthier options. These products often contained more sugar and nearly the same calories as their full-fat counterparts.

Many people don’t realise that these low-fat foods are often unhealthier than their full-fat versions for several reasons:

First, they’re typically loaded with sugar, salt, or starch to compensate for the flavour and texture that fat provides. A “low-fat” yoghurt might contain 22 grams of sugar compared to 7 grams in plain yoghurt, essentially turning a healthy food into dessert.

Second, they deprive us of essential nutrients. Fat is crucial for the absorption of fat-soluble vitamins (A, D, E, and K). Healthy fats from sources like ghee, nuts, olive oil, and fatty fish are beneficial for heart health, brain function, and overall well-being.

Third, removing fat eliminates the satiety factor. Fat contributes significantly to feeling full after eating. Low-fat foods often leave people less satisfied, leading to overeating or frequent snacking – precisely the opposite of what was intended.

Fat contributes to satiety. Low-fat foods may leave people feeling less satisfied, leading to overeating or frequent snacking. The perception that low-fat foods are “healthier” can also cause people to consume larger portions, negating any calorie savings.

The food industry’s response to this shift was especially troubling. Initially, food manufacturers were deeply concerned about how fat was rapidly becoming the bad guy. They knew that a product with much less fat was likely to be much less tasty. But it wasn’t long until they spotted a lucrative opportunity – they simply replaced fat with sugar.

Throughout the 1980s and 1990s, grocery shelves were stacked high with low-fat products containing just as many calories as their full-fat predecessors. Because these foods were marketed as “healthy,” consumers snacked freely, believing they were eating guilt-free pleasures.

To ensure this new revenue stream continued, the food industry funded research that downplayed the negative health impact of sugar and suppressed their own research8 that linked sugar to heart disease. They also made sure to highlight and reiterate health concerns around fat.

Science has moved on since the 1980s, and the all-fat-is-bad theory did not stand up to scrutiny. Recent studies show there is no good evidence that – compared with moderate-fat diets – low-fat diets reduce obesity or the risk of type 2 diabetes or heart disease. In fact, eating “good” fats, such as those in nuts or oily fish, might reduce the risk of heart disease.

Almost as problematic as our fear of fat has been our misplaced trust in simplistic metrics like the glycemic index. The glycemic index (GI) is a tool used to rank carbohydrates based on their effect on blood glucose levels. While it has gained popularity for its role in managing diabetes and promoting healthier eating, it is an incomplete marker for several reasons.

The glycemic load (GL) is generally considered a better marker than the glycemic index for assessing the impact of food on blood sugar levels. GI measures how quickly carbohydrates in a food raise blood sugar levels compared to pure glucose, scored on a scale of 0–100. However, it doesn’t account for the quantity of carbohydrates consumed, which limits its practical application for real-world dietary planning.

Excerpted with permission from Sick Nation: Inside India’s Lifestyle Disease Epidemic and How to Fix It, Karan Sarin, Wyzr.