Throughout most of human history, our diets consisted of natural foods such as meat, fish, nuts, seeds, and seasonal fruits. Agriculture, which introduced grains and larger quantities of carbohydrates, has only been a factor for about 12,800 years, a relatively minor period in human dietary history.

Ultra-processed foods are a predominantly modern invention,surging in consumption within the last century. In the United States, approximately 70% of people's diets now consist of these highly processed foods.

In 1977, the United States introduced dietary guidelines aiming to address unhealthy trends. These guidelines recommended reducing fat and protein intake while increasing carbohydrate consumption, a sharp departure from our ancestors' diet.

The current dietary approach mirrors obesogenic rat chow used in labs to fatten rodents quickly. While the guidelines recommend 30% of energy from fats, the fat is often sourced from oils that are not conducive to healthy metabolism. When combined with high carbohydrate intake, this can lead to excessive insulin production, resulting in obesity and diabetes.

• High carbohydrate consumption parallels lab diets known for causing rapid weight gain in rodents.
• Guidelines' emphasis on low-fat but high-carb diets coincided with an increase in processed food popularity.

Fat is very effective at making you fat if you also have a lot of carbohydrates.

The guidelines still emphasize low-fat diets and allow for significant sugar intake. However, they encourage consuming whole foods over processed ones, which aligns more closely with traditional human diets. This focus on food quality is a step towards improved public health.