From Dr. Greger:
Saturated Fat Causes Artery and Lung Inflammation

From the transcript:

I’m old enough to remember this:

In a series of videos I did about a decade ago, I discussed this landmark research showing that a single high-fat meal could cripple artery function within hours of consumption, compared to no change in the low-fat meal. The high-fat meal that so crippled artery function included Sausage and Egg McMuffins from McDonalds. How do we know the sausage, egg, or cheese was to blame? What about the crappy carbs in the biscuits or something? Because the low-fat meal that didn’t impair artery function was a sugary mess of carby Frosted Flakes.

And just when your artery function finally starts to recover five or six hours later? Lunchtime! And, your arteries may get whacked with another load of meat, eggs, dairy, or oil. Why does it matter so much what happens after a meal within your body? Because most of us spend about 16 hours a day in that after-a-meal state, constantly hammering our arteries. No wonder cardiovascular disease is our #1 killer.

I didn’t know a high-fat meal could have a similar effect on the lungs:

And it doesn’t just inflame the arteries in our heart, but our lungs as well. “A high-fat challenge increases airway inflammation and impairs bronchodilator recovery in asthma.” Have asthmatics cough up sputum from their lungs four hours after the same kind of high-fat meal, and inflammatory cells shoot up in the high-fat meal group. In terms of lung function, give them two hits of their inhalers (containing a drug called albuterol or Ventolin) and their airways open up as they should—after the low-fat meal. But after the high-fat meal, the same inhaler doses don’t work as well, crapping out after a few hours because of all the extra inflammation in their lungs. What you eat can determine how well you breathe.

Okay, but that was asthmatics. But even in nonasthmatic subjects, you get that same spike in inflammatory cells in sputum coughed out of your lungs four hours after eating what was, in this case, a Jimmy Dean Meat Lovers Breakfast Bowl.

And … pizza:

And there aren’t only more inflammatory cells; there is a doubling of the amount of pro-inflammatory oxidized LDL cholesterol sucked up by the type of white blood cells that go on to form foam cells. Those are the cells that build up the inflamed pus in your artery wall that leads to heart attacks. And all this happens within just hours of eating pizza, in this case.

Here he’s referencing a pretty new study (the last one in the Resources list below), that sheds more light on the effect of endotoxins, which were thought to be integral in arterial inflammation. It may be the fat after all:

The fat in your blood goes up, and so do your endotoxin levels. Endotoxins are the components of bacterial cell walls, and foods like meat can be so contaminated with bacteria—alive and dead—that they accumulate endotoxins. And we’re talking about both red meat and white meat.

But, recent research (published in 2020) suggests the main culprit may not be endotoxins after all, but the fat itself. The saturated fat floating in your blood after an unhealthy meal may be inducing the inflammation more directly.

Resources:

You’re only as old as your arteries: translational strategies for preserving vascular endothelial function with aging. Physiology (Bethesda). 2014;29(4):250-64.

Effect of a single high-fat meal on endothelial function in healthy subjects. Am J Cardiol. 1997;79(3):350-4.

Human postprandial nutrient metabolism and low-grade inflammation: a narrative review. Nutrients. 2019;11(12):3000.

A high-fat challenge increases airway inflammation and impairs bronchodilator recovery in asthma. J Allergy Clin Immunol. 2011;127(5):1133-40.

Does chronic physical activity level modify the airway inflammatory response to an acute bout of exercise in the postprandial period? Appl Physiol Nutr Metab. 2017;42(2):173-80.

Consumption of a high-fat meal was associated with an increase in monocyte adhesion molecules, scavenger receptors, and Propensity to Form Foam Cells. Cytometry B Clin Cytom. 2018;94(4):606-12.

Accumulation of stimulants of Toll-like receptor (Tlr)-2 and TLR4 in meat products stored at 5 °C. J Food Sci. 2011;76(2):H72-9.

Endotoxin may not be the major cause of postprandial inflammation in adults who consume a single high-fat or moderately high-fat meal. J Nutr. 2020;150(5):1303-12.