Sunday, February 1, 2015

Yogurt does not deplete the liver's energy stores

Background

"A spoonful or two of acidic yogurt isn't harmful, but a cupful of the
acidic type can be enough to deplete the liver's energy stores
,
because lactic acid is converted to glucose in the liver, requiring
energy. The "strained" type that isn't acidic is similar to cottage
cheese and is safe." – Ray Peat (Email advice)

Calculation

For safety, I calculated the required energy to metabolize the lactic acid of 2 cups of yogurt (500g).
According to this source, yogurt contains 1.08% lactic acid.
500g yogurt would then contain 5.4g lactic acid.
5.4g lactic acid equals 5.34g lactate + 0.06 hydrogen (dissociates in gut).
Lactate is converted to glucose in the liver's Cori cycle.
6 mol of ATP is required to convert 2 mol of lactate into 1 mol of glucose.
5.34g lactate ~ 0,06 mol lactate
0,06 mol lactate requires 0.18 mol ATP to convert it into glucose.
To produce 0.18 mol ATP, 0.005 mol glucose is used up (1 mol glucose produces 36 mol ATP).
0.005 mol glucose = 0.9008g Glucose.

Conclusions

To completely metabolize the lactic acid of 500g yogurt, you only need 0.9g of glucose. Given that a human liver contains around 100-200g of stored glycogen and 500g of yogurt contains 23.5g lactose itself (Glucose+Galactose), this amount is totally negligible and does not deplete the liver's energy stores in a relevant way.

1 comment:

  1. Anonymous2/2/15 22:51

    He may mean lactic acid produced live (bacteria eating the carbs you have eaten, as all things mix in digestive system). If you open a yogurt or kefir and leave it at room temp, you get an explosion in lactic acid production.

    ReplyDelete