NDSU Professor Studies Fat Gains in Pig Diets
Findings may give insight into human diets
Published: Thursday, February 13, 2014
Updated: Thursday, February 13, 2014 09:02
With more than 1/3 of Americans obese, health is a matter that weighs on the United States today.
Eric Berg, an NDSU professor and the associate head of animal sciences, recently put pigs on differing diets in hopes of uncovering facts and statistics that could, in turn, be related to human eating patterns. The control group received a vegetarian diet, while the test group received a ground-beef ration.
The meat-eating pigs saw a 38 percent increase in body fat compared to a 50 percent increase in the vegetarians, even though the test group consumed more calories and had 36 percent fat from saturated red meat.
“The big take-home was both test groups got fat,” Berg said, but the selection of swine that received the ground-beef diet gained less fat than the control group.
“(The experiment) was really testing the hypothesis that you hear from the remnants of the Atkins diet, that people can eat as much bacon or as much fatty hamburger as they want, and they won’t gain any weight,” Berg said. “Is that true? Is that testable?
Berg and his team used pigs as surrogates in the tests for practical reasons.
“The reason we chose pigs,” Berg said, “is that the National Institute of Health recognizes pigs as a perfect model to use as a substitute for humans when you study how food affects their whole physiology.”
After securing some money for experimental uses, like buying feed, and receiving approval from the Animal Care and Use Committee, the experiment could commence.
“When we formulate a diet for pigs, we know down to the micronutrients—we know everything to make that pig thrive,” Berg said.
He said the vegetable diet added 15 percent corn oil for unsaturated fat in order to model a human’s average daily allowance.
As it is with every scientific experiment, researchers must keep all variables constant, except the experimental variable. All tested pigs received necessary nutrients needed to sustain a healthy life. All of the tested pigs, all of which were females, had the same boar as a father. The pigs were also all raised in a same-sized, spacious pen where they started their diet when they had the same amount of body fat.
Both groups could eat as much food as they wanted, which also led to some interesting findings for Berg and his team.
“I was surprised that they ate so much,” Berg said of his pigs. “Previous research shows that pigs will eat until their nutrient requirements are met and then they’ll stop, but they didn’t.”
The pigs ate over 20 pounds per day. The study was supposed to last more than six months, but the pigs ate the research team out of money.
“Some people say calories don’t matter, it’s the type of food you eat,” Berg said. “Well, in this case, I think calories do matter because the ground-beef pigs, even though, by our calculations, they ate a lot more calories, but they gained less fat.”
Kim Vonnahme, an associate professor of animal science at NDSU, is a walking testimonial to Berg’s findings. Vonnahme told The Forum that she has lost nearly 50 pounds since changing her diet to consume less carbs and more fat.
The controversial Atkins diet, created by nutritionist Robert Atkins, has seen its popularity fluctuate throughout the years, but its core concept is that of a low-carbohydrate intake and high-protein and fat-consumption diet.
While lost weight may occur using this diet, critics claim that eating too much red meat can cause cholesterol levels to rise, causing cardiac issues.
Berg’s preliminary numbers also show that insulin levels were stable over the testing period for the meat eaters, while the vegetarians slowly saw their levels increase.
Prevailing theories suggest that as a person becomes fat, they are also developing pre-diabetes and other conditions, Berg said.
“We are trying to add some science behind some of these diets like the Paleo or Atkin’s Diets,” Berg said. “If I start talking about a low-carbohydrate diet to medical doctors, a lot of them tune out. But if I start talking about a low-glycemic diet — that, that’s the new word. That makes scientific sense to them. The rest are just fad diets.”
Although the numbers are telling, nobody has claimed to find the cure for obesity or how to make one skinny for swimsuit season.
“While we are confident in the data, really, all you can take home is saying that these significant differences were, in this particular genotype of pigs given these particular set of circumstances, what happened,” Berg said.
What the experiment does do is set the foundation for future tests, which ultimately could lead up to humans being tested on their diets.
As for now, Berg has submitted four abstracts for presentation this March for the Midwest section of the American Society of Animal Science. The data is also set to be presented to the American Meat Science Association this June.
“I got tired of meat getting the bum rap, so I dug out some science,” Berg said.