You Are What You Eat: How Fat Affects Your Bloodstream

July 29, 2009 — -- After being shown the immediate impact high-calorie meals can have on your bloodstream, viewers challenged ABC News to show what a healthier meal might do to the body.

"I watched you showing the effects of eating fast food on the blood stream this morning. Now show me the same test done with homemade food in a normal household and a twigs and berries diet at home. Be fair and show those results," one viewer wrote in to ABCNews.com. "I have an extra 20 [pounds] on me from eating at a fast food place for 2 years. I just want you to prove to me that the results are indeed different eating so called healthy food and twigs and berries."

So ABC News correspondent Yunji de Nies and producer Jon Garcia headed to the University of Maryland's Medical Center again — this time to show how lighter fare would affect their systems.

In the first fatty food experiment, de Nies and Garcia ordered food from some of America's most popular restaurant chains.

They each packed away more than 6,000 calories and more than 10 times the amount of saturated fat the government recommends.

The result: two hours later the fat was still chugging through their veins.

But when they had a much healthier lunch, the results were drastically different.

How a Healthier Diet Affects Your Bloodstream

De Nies and Garcia opted for healthier meals from the very same restaurants they used in the last experiment. This time they began their meals with soybeans, before moving on to salmon, grilled veggies and rice. Lunch ended with apple pie the pair shared.

Lighter Meals Make a Difference in Health

The lighter lunch packed about 1,000 calories and three grams of saturated fat.

When lab technicians tested Garcia's blood two hours after the meal, there was almost no discernible change in the amount of fat in his blood stream from the sample taken before the meal.

That was in stark contrast to the original experiment, when there was an undeniable increase in the level of fat in his blood after the meal.

"[The food] was healthy, didn't raise the blood fat levels and, therefore, likely to not have an abnormal or unhealthy effect on your arteries," Dr. Mike Miller of the University of Maryland told Garcia.

De Nies' results proved so extraordinary that they surprised even the doctors.

Not only was her blood clear of fat, but her arteries were actually more expanded and healthier after she'd eaten the salmon than they were before.

"We've seen that with people eating fish," said Dr. Robert Vogel of the University of Maryland. "This was a much healthier meal for you, and it actually made your arteries healthier."

Her arteries were so much healthier that doctors said one meal had the same effect on de Nies' arteries as if she had just gone for a run. The final lab results showed that De Nies' arteries had a 25 percent improvement.

"The great news here is that you can go to virtually any restaurant or fast-food chain and find a healthy food choice," Miller said.

Cardiovascular disease is the nation's No. 1 killer, but the doctors said that this experiment shows you how much difference what you eat at every meal can really make in your health.

"It's not so much what we shouldn't do," Vogel said. "It really is how we should live what is really good for us."