Dairy Attenuates Weight Gain to a Similar Extent as Exercise in Rats Fed a High-Fat, High-Sugar Diet

Abstract

This study provides evidence that dairy limits weight gain to a similar extent as exercise training and the combined effects are greater than either intervention alone. While exercise training reduces weight gain through increases in energy expenditure, dairy appears to increase lipid excretion in the feces.

Exercise and Dairy Protein have Distinct Effects on Indices of Liver and Systemic Lipid Metabolism

“…Four‐week‐old male Sprague Dawley rats (Charles River Laboratories, Wilmington, Massachusetts) were group housed (three to four per cage) in a temperature‐ (22°C) and humidity‐controlled room with a 12:12‐hour reverse light‐dark cycle and were given free access to standard chow and water. After 1 week of acclimatization, and as we have previously reported in these same animals , rats were fed an HFHS diet for 8 weeks to induce obesity. Diets were prepared in house, as we have previously , and formulated to meet the nutritional requirements of rodents ; detailed dietary analysis is shown in Table .…”

“…Fat content in the diets was derived from equal amounts of soybean oil (55% linoleic acid, 23% oleic acid, 10% palmitic acid, and 8% linolenic acid) and lard (44% oleic acid, 26% palmitic acid, 13% stearic acid, and 10% linolenic acid); these represent the sole dietary fat sources. At ~ 12 weeks of age, as previously described , rats were assigned to one of four weight‐matched, isocaloric HFHS groups for 6 weeks: (1) casein‐sedentary, (2) casein‐exercise, (3) SMP‐sedentary, and 4) SMP‐exercise. Nonfat SMP (MP Biomedical, Santa Ana, California) was used as the sole protein source in the dairy diet, and casein was the protein source in the control diet (Table ).…”

“…The animals exercised at 10 m/min at 0% incline for 60 minutes for the first week, and the speed and incline were gradually increased to 15 m/min at 0% incline for 60 minutes by the second week. By the third week, and for the remainder of training, the speed and incline of the treadmill were set to 20 m/min at 5% incline for 60 minutes .…”

“…Along these lines, dairy milk extract reduced steatosis, hyperlipidemia, and expression of lipogenic genes (e.g., Acc1 , Fasn , Scd1 ) in livers of high‐fat‐fed mice, independently of changes in body weight . We have also shown that dairy (skim milk powder [SMP]) reduced the expression of lipogenic genes, including sterol regulatory element binding transcription factor 1 ( Srebp1c ) and peroxisome proliferator activated receptor gamma ( Pparg) and reduced total hepatic lipid content in obese rats that were fed a high‐fat, high‐sugar (HFHS) diet .…”

“…Exercise improves liver function and reduces total hepatic lipid content , but there remains a lack of consensus on the effects of exercise on liver fatty acid composition . Moreover, despite its ability to reduce total lipid content and lipogenic gene expression , the effects of dairy on hepatic fatty acid composition have never been explored. The current project was designed to explore the individual, and combined, effects of dairy (in the form of SMP) and exercise on indices of systemic and liver lipid metabolism.…”