Essentials

A 2016 paper combines data from multiple prospective cohort trials to show low sodium intake has a stronger and more universal association with increased mortality than high sodium intake. The reviewers found the only population that benefits from sodium restriction is hypertensive individuals consuming more than 6 grams of sodium per day (only 10% of the combined study population). The remaining 90% would expect to receive no health benefit or even increased health risk by reducing sodium intake. The reviewers suggest recommendations similar to those of the American Heart Association may actually be harmful for the majority of Americans.

Metabolic training refers to conditioning exercises intended to increase the storage and delivery of energy for any activity. Ultimately, the CrossFit position on metabolic conditioning, or “cardio,” is summed in two points: Anaerobic training can match endurance training for aerobic benefits. Metabolic training with varying and mixed exercise modalities avoids specificity of adaptation allowing for additional first wave-cardiovascular/respiratory adaptations and increased functional strength.

“Something about the industrial processing of food makes us more likely to overeat, according to a new study. Volunteers ate more and gained more weight on a heavily processed diet than an unprocessed one, even when the two diets had the same available calories and nutrients. The study is ‘a landmark first,’ and a ‘shot over the bow’ in a debate over the health of processed food, says Steven Heymsfield, an obesity researcher at Louisiana State University’s Pennington Biomedical Research Center in Baton Rouge who was not involved with the work. But some experts question whether the study controlled for important differences between the diets.”

This widely reported 2019 paper suggests ultra-processed diets increase caloric intake, independent of other dietary factors; two subsequent comments debate our ability to extrapolate health and diet advice from these results.

Walking, jumping, kicking, running, lifting — almost every task we take for granted as a normal part of human existence relies, at least in part, on the knee. The knee joint is a slight modification of a simple condyloid hinge joint that allows extension and flexion. Unlike other condyloid hinge joints, the knee allows for a very small amount of lateral and medial rotation. The bones of articulation in the knee are the femur of the thigh, the tibia and fibula of the lower leg, and the patella (or kneecap).

Our purpose here is to show specifically how a simple goal, like rowing a seven-minute two thousand meters, can not only be systematically and deliberately approached from multiple protocols, but can generally encourage similar thinking in pursuing other fitness milestones.

Prof. Tim Noakes describes Gerald Reaven’s research on the carbohydrate metabolisms of patients with coronary heart disease (CHD), which demonstrated patients with hypertriglyceridemia were more likely to be insulin resistant. Noakes also highlights a series of studies conducted by Reaven and colleagues that explored the effects of high- and low-carbohydrate diets on blood triglyceride concentrations — studies that ultimately revealed the American Diabetes Association’s high-carb, low-fat dietary recommendations may have been increasing diabetics’ risk of CHD.

“A low-sodium diet has a shaky foundation in heart failure, a systematic review showed. Out of more than 2,600 studies on sodium restriction in heart failure, only nine small trials with a total sample of 479 -- none of which were free from bias -- made it into an analysis by a group led by Kamal Mahtani, PhD, of the University of Oxford, England. In the end, the investigators found ‘no clinically relevant data on whether reduced dietary salt intake affected outcomes such as cardiovascular-associated or all-cause mortality, cardiovascular-associated events, hospitalization, or length of hospital stay,’ they reported online in JAMA Internal Medicine.”