Sodium bicarbonate (baking soda) is a supplement that provides dietary bicarbonate, which can increase serum levels of bicarbonate (normally produced by the kidneys) and subsequently buffer acid production in the body. The main mechanism of action of sodium bicarbonate is in negating the effects of acidosis. It provides benefits both in situations of chronic mild acidosis, commonly seen in metabolic ailments or during aging as kidney function slowly declines, and in exercise-induced acidosis.
In athletes, the standard doses of sodium bicarbonate supplementation (200-300 mg/kg) tend to reliably benefit performance when failure on the exercise is associated with metabolic acidosis, aka “the burn.” Sports where failure occurs due to the cardiorespiratory system or due to force production by the central nervous system (e.g., single sprints or rowing in elite rowers) do not appear to reliably benefit from supplemental bicarbonate.
Benefits of sodium bicarbonate can be observed with a single dose taken 60-90 minutes before exercise, but supplementation should be approached cautiously as it can cause gastrointestinal side effects if too much is taken at once or, if it’s consumed too rapidly.
Additionally, 5 g of sodium bicarbonate taken daily appears to be somewhat effective in reducing acidosis induced by the diet or the aging process (although using potassium bicarbonate appears to be better), and therefore it may reduce the rate of bone loss over time in susceptible populations.
There are mechanisms in place for sodium bicarbonate to be a fat-burning agent (it increases ketone production and lipolysis and causes a minor increase in metabolic rate), but these have not yet been linked to actual weight loss in trials.