A portion of protein after training stimulates muscle growth. Most of the research that confirms this refers to protein shakes, and especially those based on whey. But a portion of meat works just as well write Canadian sports scientists at McMaster University in Applied Physiology, Nutrition, and Metabolism.
The researchers did an experiment with 35 men with an average age of 59 years. During the days preceding the experiment the men consumed 1 g protein per kg bodyweight per day.
The researchers got the men to train one leg on a leg extension machine, but not the other leg. The men did three sets of 8-10 reps.
After the leg training session the researchers gave the men 0, 57, 113 or 170 g fried minced meat. That’ s the equivalent of 0,12, 24 or 36 g protein. The minced meat contained 15 percent fat. So the 170-g portion provided 26 g fat.
After the meal the researchers took samples from the men’s leg muscles, and measured the myofibrillar protein synthesis [MPS] – put simply, muscle fibre production. The figure shows that the minced meat stimulated the production of muscle fibre protein in the untrained leg [FED], and that this effect was stronger in the trained leg [FED+EX].
Meat is a slow protein, according to the figures above. These show that four hours after intake the concentration of essential amino acids and BCAAs continued to rise.
The researchers aren’t sure what would happen if the men consumed more meat than the 170 g after a workout, but they suspect that 170 g is about the optimum amount.
The study was financed by the National Cattlemen’s Beef Association [beef.org] and by Canada Beef [canadabeef.ca].
Appl Physiol Nutr Metab. 2013 Feb;38(2):120-5. doi: 10.1139/apnm-2012-0092. Epub 2012 Nov 9.
Dose-dependent responses of myofibrillar protein synthesis with beef ingestion are enhanced with resistance exercise in middle-aged men.
Robinson MJ, Burd NA, Breen L, Rerecich T, Yang Y, Hector AJ, Baker SK, Phillips SM.
a Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.
Aging impairs the sensitivity of skeletal muscle to anabolic stimuli, such as amino acids and resistance exercise. Beef is a nutrient-rich source of dietary protein capable of stimulating muscle protein synthesis (MPS) rates in older men at rest. To date, the dose-response of myofibrillar protein synthesis to graded ingestion of protein-rich foods, such as beef, has not been determined. We aimed to determine the dose-response of MPS with and without resistance exercise to graded doses of beef ingestion. Thirty-five middle-aged men (59 ± 2 years) ingested 0 g, 57 g (2 oz; 12 g protein), 113 g (4 oz; 24 g protein), or 170 g (6 oz; 36 g protein) of (15% fat) ground beef (n = 7 per group). Subjects performed a bout of unilateral resistance exercise to allow measurement of the fed state and the fed plus resistance exercise state within each dose. A primed constant infusion of l-[1-(13)C]leucine was initiated to measure leucine oxidation and of l-[ring-(13)C(6)]phenylalanine was initiated to measure myofibrillar MPS. Myofibrillar MPS was increased with ingestion of 170 g of beef to a greater extent than all other doses at rest and after resistance exercise. There was more leucine oxidation with ingestion of 113 g of beef than with 0 g and 57 g, and it increased further after ingestion of 170 g of beef (all p < 0.05). Ingestion of 170 g of beef protein is required to stimulate a rise in myofibrillar MPS over and above that seen with lower doses. An isolated bout of resistance exercise was potent in stimulating myofibrillar MPS, and acted additively with feeding.
PMID: 23438221 [PubMed - in process]