Saturated fat comes from animal foods, including dairy products (butter, cheese, cream), meats (chicken, hamburger), and eggs.

Here’s the study:
Replacement Of Saturated With Unsaturated Fats Had No Impact On Vascular Function But Beneficial Effects On Lipid Biomarkers, E-selectin, And Blood Pressure: Results From The Randomized, Controlled Dietary Intervention And Vascular Function (DIVAS) Study, American Journal of Clinical Nutrition, July 2015

195 men and women, a wide age range (21 to 60), with “moderate cardiovascular disease risk” were split into three groups:

• High saturated fat (SFA)
• High monounsaturated fat (MUFA)
• High polyunsaturated fat (PUFA)

Everyone ate the same amount of calories. All diets were high-fat: 36% of total calories came from fat. They consumed their respective diets for 16 weeks.

Those that ate less saturated fat, replacing it with unsaturated fat, lowered their total and LDL cholesterol, improved their blood pressure, and lowered a biomarker for inflammation and cancer (E-selectin):

Replacement with MUFAs or n–6 PUFAs lowered fasting serum total cholesterol (−8.4% and −9.2%, respectively), low-density lipoprotein cholesterol (−11.3% and −13.6%), and total cholesterol to high-density lipoprotein cholesterol ratio (−5.6% and −8.5%) (P ≤ 0.001). These changes in low-density lipoprotein cholesterol equate to an estimated 17–20% reduction in CVD mortality.

Substitution of SFAs with MUFAs attenuated the increase in night systolic blood pressure (−4.9 mm Hg, P = 0.019) and reduced E-selectin (−7.8%, P = 0.012).

Saturated fat comes primarily from animal food. So, people in this study who reduced their saturated fat intake were reducing their intake of foods like butter, cheese, chicken, bacon, sausage, hamburgers, steak, and eggs.

When people tell you that saturated fat is good for you, or that there are no studies that show reducing satured fat is beneficial, show them this. Tell them there are a lot more where this came from.