Arciero’s findings add to a growing body of evidence on the benefits of a ‘protein-pacing’ caloric restriction (P-CR) diet, which cuts back on calories and features four-six meals a day, each of which includes 20 to 25 grams of protein. Participants in Arciero’s study also engaged in intermittent fasting.
His research results are discussed in “Serum Polychlorinated Biphenyls Increase and Oxidative Stress Decreases with a Protein-Pacing Caloric Restriction Diet in Obese Men and Women," which is published in the latest edition of the International Journal of Environmental Research and Public Health (Arciero-Protein-Pacing & Toxins).
A professor of health and exercise sciences at Skidmore, Arciero also is director of the college’s Human Nutrition and Metabolism Laboratory. Skidmore students, health services staff and other colleagues assisted with the P-CR diet research.
The International Journal of Environmental Research and Public Health article is the third publication in recent months to report on Arciero’s findings on the impact of a P-CR diet. Previous articles, including the July 30 edition of Nutrients (Arciero-Protein-Pacing & Body Composition) and the August 29 edition of Frontiers in Physiology (Arciero-Protein-Pacing & Heart Health), highlighted improvements in body composition and vascular health, respectively.
In each case, Arciero first compared the results of the P-CR diet between obese men and women following a 12-week weight loss diet and subsequently compared the P-CR diet with those achieved by the heart-healthy diet over a 52-week period. The 12-week P-CR diet was equally effective at reducing body weight (>24 lbs, 10%), oxidative stress (25%), and arterial stiffness (12%) and increasing toxin release (25%) in women and men. Following the 52-week phase, P-CR demonstrated improvements over the traditional heart-healthy diet in maintaining weight loss; reducing artery stiffness; and releasing toxins.
“The heart-healthy diet has proven health benefits,” Arciero said, “but it’s important to continue to research and identify additional dietary strategies that may help improve individual and public health.”
A toxin-fighting response
His findings on toxins can help allay concerns that weight loss—which releases toxins into the blood—could have a negative effect on dieters’ health.
Environmental pollutants and other toxins are stored in fatty tissue. During weight loss, fat breaks down and toxins are discharged into the bloodstream. Scientists have expressed concern that the released toxins could increase dieters’ oxidative stress and their risk of developing serious conditions, including hormone (endocrine) disruption (reproductive and fertility problems), heart disease, cancer, Alzheimer’s disease and Parkinson’s disease.
Arciero’s research findings—that a P-CR diet does not increase disease markers and, in fact, can aid detoxification and reduce oxidative stress—help reduce those fears. Furthermore, the findings suggest that those who are not overweight or obese could also benefit from a P-CR diet.
“Although weight loss typically leads to improved health, we know that in those who are overweight and obese—and, therefore, storing excessive toxins—there is the potential for the release of toxins to impact the body in negative ways,” Arciero explained. “We wanted to capture the release of those toxins and the body’s response.
“What we found was that the body compensated by increasing antioxidants. In response to this flood of PCBs, the body was coming to its own defense, scavenging and squelching the toxins. We had a healthy weight-loss intervention,” Arciero added.
The objective of the first 12-week phase was to assess the ability of a P-CR diet to achieve successful weight loss (defined as 10 percent of starting body weight) and this was achieved, with a mean weight loss of over 25 pounds.
During this phase, women consumed 1,200 calories per day and men, 1,500. Of those, 30 percent came from lean protein, 45 percent from unrefined carbohydrates, and 25 percent from healthy fat. One day a week, participants followed an intermittent fast/cleanse, consisting of 300 to 450 calories from antioxidant rich plant-food sources.
The second phase (52 weeks) of the research compared the results of the P-CR diet and a more traditional heart-healthy diet. All dieters consumed roughly the same number of calories: approximately 1,900 for both groups. P-CR dieters fasted/cleansed either once every two weeks or once a month. Those on the heart-healthy diet followed the guidelines of the National Cholesterol Education Program, consuming 35 percent of calories as fat and 50 to 60 percent as carbohydrates. Heart-healthy dieters also ate 20 to 30 grams per day of fiber and consumed fewer than 200 milligrams per day of dietary cholesterol.
At the end of the 12-month period, the results for the two groups deviated significantly, with the P-CR diet outperforming the heart-healthy diet for both maintaining weight loss, reduced blood vessel stiffness and eliminating toxins.
Research participants who remained on the P-CR diet regained about 1.5 pounds of the weight they’d lost and continued to eliminate toxins. Those on the heart-healthy diet, however, regained 12 pounds. Most of it was fat—and that fat may likely have (re-)stored toxins.
“We have scientific evidence that it’s the quality of your diet that matters,” Arciero said. “Through diet alone, we can favorably impact the detoxification process, decrease oxidative stress levels, reduce blood vessel stiffness and enhance weight loss. That’s an important public health message.”
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