What caused the rise in heart disease rates in the 20th century, and what role did diet play?

Question

Accepted Answer

The most important dietary story is not simply “fat caused heart disease.” In the 1960s, the Sugar Research Foundation paid Harvard scientists $6,500 — roughly $50,000 in later dollars — for a 1967 New England Journal of Medicine review that downplayed sugar’s role in coronary heart disease and emphasized saturated fat and cholesterol instead. The industry set objectives, supplied articles, reviewed drafts, and the funding was not disclosed. Cristin Kearns and colleagues exposed this in JAMA Internal Medicine in 2016. That matters because it helped steer decades of public health advice toward “eat less fat” while sugar and refined carbohydrates escaped comparable scrutiny.

The diet question breaks into several competing claims:

### 1. The sugar-cover-up claim: sugar and refined carbs were pushed out of the spotlight  
This claim says the rise in heart disease was strongly tied to increasing consumption of sugar, sucrose/fructose, refined carbohydrates, and processed foods — but the public was taught to fear fat instead. The Sugar Research Foundation’s Project 226 was designed to counter research linking sugar to coronary heart disease and shift attention toward saturated fat.

A key figure here is John Yudkin, who warned in *Pure, White and Deadly* that sugar was a major driver of heart disease and metabolic disease. His work was marginalized while the fat hypothesis became institutional orthodoxy.

### 2. The guideline-corruption claim: public advice amplified the wrong villain  
The 1977 McGovern-era dietary recommendations and later U.S. dietary guidance emphasized reducing total fat, saturated fat, and cholesterol. One of the scientists involved in the sugar-funded Harvard review, D. Mark Hegsted, later helped shape federal nutrition policy.

The result was a food environment where “low-fat” often meant “higher sugar.” Manufacturers removed fat, then added sugar, refined starches, and additives to make processed foods palatable. This helped normalize low-fat, high-carbohydrate eating patterns while obesity, diabetes, and metabolic disease climbed.

### 3. The powerful-interests claim: industry shaped science, not just marketing  
The sugar industry used tactics compared to tobacco: funding favorable reviews, creating doubt, influencing advisory committees, lobbying policymakers, and attacking inconvenient science. Later beverage-industry behavior followed the same pattern: Coca-Cola funded the Global Energy Balance Network with $1.5 million to emphasize exercise over diet in obesity discussions, and industry-funded beverage studies were reported to be five times more likely to find no link between sugary drinks and weight gain.

So diet played a role not only biologically, but politically: the public was handed a distorted map.

### 4. The misconception-debunking claim: saturated fat alone is an oversimplified explanation  
This claim pushes back against the neat story that saturated fat was the clear, sole cause of 20th-century heart disease. The evidence base behind aggressive fat restriction had weaknesses: selective datasets, reliance on surrogate markers like serum cholesterol, incomplete trial publication, and later challenges to the idea that replacing saturated fat with linoleic-acid-rich oils reliably reduces coronary events or mortality.

That does not mean diet was irrelevant. It means the official diet narrative became too narrow: “reduce fat” crowded out “reduce sugar, refined carbs, and ultra-processed foods.”

### Bottom line  
The rise in 20th-century heart disease was tied to a modern food environment increasingly rich in refined sugar, processed carbohydrates, industrially reformulated foods, and misleading low-fat products. Diet mattered enormously — but the public was steered toward blaming saturated fat while sugar’s role in heart disease, obesity, diabetes, and metabolic dysfunction was minimized for decades.

The practical lesson is simple: don’t evaluate heart-disease diet advice by whether it says “low fat.” Ask who funded the research, whether sugar and refined carbohydrates were seriously examined, and whether the recommendation protects public health or a market.

Sugar, Fat, and the Politics of Nutrition

About this Capsule

4 eye-opening claims about sugar and health

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Major reasons heart disease rates rose

1. The sugar-cover-up claim: sugar and refined carbs were pushed out of the spotlight

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