What’s SAD About the Standard American Diet?

By Shannon Kasun, Neuroscience Specialist

The acronym SAD couldn’t be more fitting for the Standard American Diet—because the health outcomes it produces are, quite frankly, sad.

This way of eating overloads our plates with processed foods, refined grains, saturated and trans fats, excess sodium, and sugar. Lots and lots of sugar.

What it lacks, however, are the very foods our bodies were designed to thrive on—the ones that don’t come in boxes, bags, or with barcodes, but from the earth itself. Fresh fruits, vegetables, whole grains, and lean proteins are pushed aside in favor of greasy, salty, and sugary temptations.

While the mouth-watering allure of the SAD may satisfy us in the moment, it is silently—and steadily—taking years from our lives.

Every day, we flood our bloodstreams with sugar with the SAD. The human body evolved to handle only small amounts—roughly 15 grams per day (Bredesen, 2020). To put that in perspective: a 16 oz caramel frappuccino from Starbucks contains about 60 grams of sugar; a can of Coca-Cola adds 39 grams; and a slice of Boston Market chocolate cake packs in 46 grams.

The sugary foods of the SAD chronically elevate blood glucose, prompting the pancreas to release more insulin in an effort to shuttle glucose into cells. Over time, however, cells become less responsive to this constant surge—leading to insulin resistance, a metabolic disorder that disrupts the body’s ability to process and use energy. Insulin resistance drives a cascade of health consequences, including type 2 diabetes, cardiovascular disease, metabolic syndrome, high blood pressure, fatty liver disease, and even neurodegenerative conditions (Kolb et al., 2023).

The consequences of sugar don’t stop there. Chronically high glucose triggers inflammation and increases oxidative stress, both of which damage the delicate lining of blood vessels (the endothelium). In fact, individuals consuming added sugars exceeding 20% of total energy intake were found to have a 39% higher risk of coronary events compared with those in the lowest intake category (Janzi et al., 2020).

Your brain isn’t safe from the sugary SAD either. A 2024 study found that individuals in the highest quartile of absolute sugar intake, relative sugar intake, and high-sugar dietary scores faced a 17.1%, 32.3%, and 25.5% higher risk of all-cause dementia, respectively, compared with those in the lowest quartile (Zhang et al., 2024).

And it isn’t just the mountain of sugar hidden in the SAD that makes it so destructive. Excess sodium drives blood pressure sky-high. Saturated fats elevate LDL cholesterol—the primary driver of atherosclerosis and heart disease. Meanwhile, processed and refined foods crowd out the nutrient-dense whole foods our bodies need to thrive.

The SAD is a delicious disaster for our health and longevity. A 2022 study suggests that replacing a typical Western diet with an optimal diet rich in whole grains, legumes, fish, fruits, vegetables, and nuts starting at age 20 could add more than 10 years to the life expectancy of women in the United States (Fadnes et al., 2022). That’s a whole decade of living gained simply by fueling your body with the foods it may not crave, but absolutely needs.

In sum

The SAD diet makes your body sad—driving disease, shortening lifespan, and robbing you of vitality. Ditch the SAD, and get glad with a diet full of real, nutrient-dense foods that fuel health for the long haul.

Explore delicious, science-backed recipes that align with your longevity goals here.

References 

Bredesen, Dale. The End of Alzheimer's: The First Program to Prevent and Reverse Cognitive Decline. Avery, 2017. 

Kolb, Hubert et al. “Insulin and aging - a disappointing relationship.” Frontiers in endocrinology vol. 14 1261298. 3 Oct. 2023, doi:10.3389/fendo.2023.1261298 

Janzi, Suzanne et al. “Associations Between Added Sugar Intake and Risk of Four Different Cardiovascular Diseases in a Swedish Population-Based Prospective Cohort Study.” Frontiers in nutrition vol. 7 603653. 23 Dec. 2020, doi:10.3389/fnut.2020.603653

Zhang, Sirui et al. “Associations of sugar intake, high-sugar dietary pattern, and the risk of dementia: a prospective cohort study of 210,832 participants.” BMC medicine vol. 22,1 298. 18 Jul. 2024, doi:10.1186/s12916-024-03525-6

Fadnes, Lars T et al. “Estimating impact of food choices on life expectancy: A modeling study.” PLoS medicine vol. 19,2 e1003889. 8 Feb. 2022, doi:10.1371/journal.pmed.1003889