A study of more than 400,000 people tracked for up to 24 years finds that those who got their dietary fat from plants versus animals had significantly lower odds of dying during the study period.

Plant-based fats' benefits included reduced odds of death due to heart disease, the research showed.

Conversely, the study "provides evidence that diets high in animal-based fats, including dairy and eggs, are associated with elevated risks of overall and cardiovascular disease mortality," concluded a team led by Dr. Demetrius Albanes, of the U.S. National Cancer Institute.

As the researchers noted, the composition of fats found in plant sources—grains, vegetables, beans or nuts—differs greatly from that sourced from animals.

"Plant-based fats are recognized for their greater composition of monounsaturated fatty acids [MUFAs] and polyunsaturated fatty acids [PUFAs], whereas animal-based fats are characterized by a higher proportion of saturated fatty acids [SFAs]," the team explained.

Bodies need fat to live, but U.S. dietary guidelines say that cutting down on saturated fats and replacing them with unsaturated fats is a healthy move.

How much would that help folks over the long term? To find out, Albanes' team looked at dietary and health data collected from 1995 through 2019 as part of the National Institutes of Health AARP Diet and Health Study.

The analysis included data on 407,531 adults who averaged about 61 years of age when they entered the study.

People were divided in five "quintiles"—from a top 20% who took in the most plant-based dietary fat each day, to the bottom 20% who took in the lowest amounts (and more animal fat).

Over the course of the study, more than 185,000 participants died, with about 58,500 dying from heart disease.

Compared to folks who took in the least amount of plant-based fats, people who placed in the highest one-fifth of participants in terms of their intake of plant-based fats had a 9% lower chance of death from any cause and a 14% lower odds of dying from heart disease, specifically, the data showed.

Looking at specific sources of plant-based fats, folks who took in the highest amount of fats from vegetable oils had a 12% lower odds for all-cause death and a 15% lower odds for death from heart disease, the study found.

Fats sourced from grains was also strongly linked to a reduced risk of all-cause and cardiovascular death, Albanes' team reported.

On the other hand, folks placing in the highest quintile in terms of animal-based fat intake faced higher odds of dying over the course of the study.

Compared to people who took in the least animal fat daily, those who consumed the most were 16% more likely to die of any cause and 14% more prone to die from heart disease.

This trend wasn't just about fats from meat: Death rates were also higher for people who ate a lot of dairy- or egg-sourced fats daily, the team noted.

The study was published Aug. 12 in the journal JAMA Internal Medicine.

So, what if a person decides to make the switch from meat, dairy and eggs over to veggies, grains and plant-based milks? The researchers calculated the benefit.

"Replacement of 5% energy [intake] from animal fat with 5% energy from plant fat, particularly fat from grains or vegetable oils, was associated with a lower risk for mortality: 4% to 24% reduction in overall mortality, and 5% to 30% reduction in cardiovascular mortality," Albanes' group estimated.