Fats and carbohydrates get all the attention, but protein– the tissue builder – is a nutrient runners shouldn’t neglect.
Four recent papers are giving runners more reason to pay attention to their protein intake. They conclude that increased protein intake can decrease “cardiometabolic risk” (of heart attacks, diabetes, etc), help lower body weight, and increase muscle synthesis, which should improve athletic success.
A report in The Journal of Nutrition looked into protein consumption in more than 23,000 American adults. Dietary guidelines recommend that we eat 0.8 grams of protein per kilogram of body weight. (That would be about 55 grams of protein a day for a 68kg person). But the study found few subjects with a protein intake that low; study authors reported that Americans typically consume protein in excess of the recommended dietary allowance.
The researchers next looked for correlations between protein intake and health markers. They found that higher protein intakes were associated with lower BMI, lower waist circumference (considered an important cause of metabolic diseases), and higher levels of the “good” HDL cholesterol. The results were particularly pronounced among overweight individuals. The researchers concluded by recommending a protein consumption of 1.0 to 1.5 g/kg of body weight.
A different protein study, followed 120,000 subjects over 16 years, looking into how long-term weight change was affected by protein consumption and GL, or glycemic load (more simple carbs = higher glycemic load). The analysis found that different proteins and different levels of GL interacted in various ways.
In general, higher GL was linked to greater weight gain, and lower GL to less weight gain. Also, from the protein perspective: Fish, nuts, and yogurt proteins were linked to less weight gain, and red meat proteins to more.
The authors noted that protein foods were usually interchanged for carbohydrates, and not for other protein foods. In other words, individuals seem capable of two smart choices at once: Eat more weight-resistant proteins (fish, nuts, yogurt), and fewer low-quality carbs. The paper was published in the American Journal of Clinical Nutrition.
A similar paper, also from the American Journal of Clinical Nutrition, reviewed the field of protein consumption and weight and health outcomes. It concluded that “higher protein diets … provide improvements in appetite, body-weight management, cardiometabolic risk factors, or all of these health outcomes.” The authors recommended protein intakes of 1.2 to 1.6 g/kg body weight per day, including 25 to 30 grams of protein per meal. (Among breakfast-skippers and cereal-lovers, morning protein consumption is often quite low.)
For athletes, protein consumption an hour or two before going to sleep may increase muscle synthesis and strength gains. That was the conclusion of an experiment published in The Journal of Nutrition. The 12-week study followed strength trainers, and the biggest changes were found in Type 2 fast-twitch muscle fibers. However, the Dutch researchers measured gains in the quadriceps muscle group, important to runners, and the results may apply to runners as well.