Impact of Weight-loss Diet on Kidney Function in Obese Population - An Interview
A recent study on 'Comparative Effects of Low Carbohydrate High-Protein Versus Low Fat Diets on the Kidney' discusses the impact of weight-loss diets on the kidneys in healthy obese patients. Dr. Allon N Friedman. M.D. Nephrology, the Department of Medicine, Indiana University, provides Medindia with additional details of the clinical trials.
Ques- Obesity, weight loss and kidney related issues are interdisciplinary subjects, what sparked the interest on the impact of weight-loss diet on kidneys?
Ans. A number of studies have been conducted on the adverse effects of weight loss diets leading to various complications or developments. It has been going on for a while, but why they occur and what was the effect of low-carb high protein diet on the kidney was not known. There wasn't sufficient information on the diet's impact on kidney function, which led to the study supported by The National Institute of Health in the U.S.
Ques- After the two years of trial period, were the participants monitored? Was there a follow up on them to verify that they did not develop any other complication?
Ans. No, there was no follow-up. The participants were involved within the clinical trial period of two years when they were supervised and were under the prescribed weight-loss diet. During the trials there weren't any major complications reported.
Ques- Two years seems like a very short period to monitor kidney functioning. How applicable are the results of your trial to actual practise?
Ans. True, two years is a short term for clinical trials and our scope was limited to that period. But we did draw our inferences from tests on proteinuria, a test conducted to check the amount of protein present through urine while the participants were on the low-carb high protein diet.
Ques - A person may lose weight due to other reasons such as following a regular workout; diet needn't be the only reason. Do you think that could have had an impact on your trials?
Ans. Yes, there are many other ways to reduce weight but our trials focused on diet intervention and the impact of the weight-loss diet in healthy obese patients and how that in turn affected the kidneys.
Ques - Was there any difference between the results in men and women?
Ans. The outcome in men and women were similar. I can't recall any difference between the way men and women responded to the diets.
Ques- People from different ethnic groups have participated in the study. Did the metabolism differ according to ethnic groups?
Ans. Majority of the participants were Anglo-American but no major differences were noted during the study among other ethnic groups.
Ques - Would the low-carb, high protein diet intended for weight loss, prescribed during the trial, be applicable to a person with no kidney disorder?
Ques - The participants were healthy obese people and that's how participants were selected for the trial. What if the person had diabetes not necessarily as serious as Type 2 diabetes, would the diet still hold good to lose weight?
Ans. Our trials were conducted on healthy obese individuals and did not include people with diabetes. But from my professional experience, I can say that people with diabetes will do well with the weight loss diet used during the trials.
The healthy obese participants were on a low-carb high-protein weight loss diet for a period of two years. However the study agrees that a follow-up will be required to ascertain long-term impact on kidney function. The study was conducted and consolidated from three centers. Other authors who contributed to the critical study include, Lorraine G. Ogden, Gary D. Foster, Samuel Klein, Richard Stein, Bernard Miller, James O. Hill, Carrie Brill, Brooke Bailer, Diane R. Rosenbaum and Holly R. Wyatt.