Effect of acute and short-term dietary fat ingestion on postprandial skeletal muscle protein synthesis rates in middle-aged, overweight, and obese men

Abstract

Muscle anabolic resistance to dietary protein is associated with obesity and insulin resistance. However, the contribution of excess consumption of fat to anabolic resistance is not well studied. The aim of these studies was to test the hypothesis that acute and short-term dietary fat overload will impair the skeletal muscle protein synthetic response to dietary protein ingestion. Eight overweight/obese men [46.4 ± 1.4 yr, body mass index (BMI) 32.3 ± 5.4 kg/m2] participated in the acute feeding study, which consisted of two randomized crossover trials. On each occasion, subjects ingested an oral meal (with and without fat emulsion), 4 h before the coingestion of milk protein, intrinsically labeled with [1-13C]phenylalanine, and dextrose. Nine overweight/obese men (44.0 ± 1.7 yr, BMI 30.1 ± 1.1 kg/m2) participated in the chronic study, which consisted of a baseline, 1-wk isocaloric diet, followed by a 2-wk high-fat diet (+25% energy excess). Acutely, incorporation of dietary amino acids into the skeletal muscle was twofold higher ( P < 0.05) in the lipid trial compared with control. There was no effect of prior lipid ingestion on indices of insulin sensitivity (muscle glucose uptake, pyruvate dehydrogenase complex activity, and Akt phosphorylation) in response to the protein/dextrose drink. Fat overfeeding had no effect on muscle protein synthesis or glucose disposal in response to whey protein ingestion, despite increased muscle diacylglycerol C16:0 ( P = 0.06) and ceramide C16:0 ( P < 0.01) levels. Neither acute nor short-term dietary fat overload has a detrimental effect on the skeletal muscle protein synthetic response to dietary protein ingestion in overweight/obese men, suggesting that dietary-induced accumulation of intramuscular lipids per se is not associated with anabolic resistance.

The Relevance of Diet, Physical Activity, Exercise, and Persuasive Technology in the Prevention and Treatment of Sarcopenic Obesity in Older Adults

“…Furthermore, both obesity and low muscle mass may be associated with anabolic resistance—the limited skeletal muscle protein synthetic response after an anabolic stimulus, for example, protein intake or physical activity ( 33 – 38 ). Nevertheless, how this mechanism works remains to be elucidated as recent studies did not find an association of obesity or fat intake on muscle protein synthesis ( 39 , 40 ).…”

Dietary Energy Partition: The Central Role of Glucose

“…Glucose is the main energy staple of our diet, and we base on 3C substrates most of our metabolic function and regulation [ 36 , 47 , 48 ]. Instead, we centered our attention on lipid (2C sources) [ 285 , 286 , 287 ], sugars as such [ 288 ], some minerals (e.g., salt), and, to a limited extent, on protein [ 289 ]. It is unclear why our flag substrate, glucose, has not been given due importance except as a marker of disease.…”

Inflammation and metabolism: the role of adiposity in sarcopenic obesity

“…There is accumulating evidence that obesity, which represents another model of lipid overload, suppresses the stimulation of MPS rates following dietary protein ingestion (144,145) , combined feeding and resistance exercise (148) in human subjects. A recent study was the first to investigate the impact of high fat feeding on MPS in human subjects (149) . This study reported that, in overweight and obese middle-aged men, neither the acute consumption of a high fat meal nor 2 weeks of overfeeding via a high-SFA diet had a detrimental effect on the MPS response to dietary protein ingestion.…”

“…This suggests that IR may be necessary to produce lipid overload-induced AR in human subjects. It will be interesting for future studies to investigate whether longer-term high fat feeding interventions that result in IR also lead to the development of AR (149) .…”