Each person seems to respond a little differently to citric acid, kind of like caffeine for some, so you would need to test it for yourself. Make sure you have been in ketosis steadily for some length of time before you do. It seems that citric acid can activate a energy cycle that is different that the one we are in and can cause a “sugar energy” chemistry in our body.
Here is what I found related to citric acid and ketosis AND ketogenic diets which is what Ideal Protein is.
“Ketosis, voluntary ketosis like you have on a ketogenic diet and not diabetes-induced ketoacidosis, relies on the Cori cycle, and lets the Krebs cycle completely collapse. That is the "alternative" cycle which is the object of "metabolic adaptation period" prior to feeling really good on a ketogenic diet. From these facts it appears logical that too much citric acid may well re-activate the krebs cycle and thus have gluconeogenesis kick in, which WILL take you of of ketosis. “
From The Ketogenic Diet by Lyle McDonald.......
“Citric acid and aspertame
In all likelihood, problems with diet soda relate to one of these two compounds, both of which are used as artifical sweeteners in diet producs. Citric acid may inhibit ketosis and diet sodas containing citric acid or apertame are not allowed for epileptic children on a ketogenic diet(14). However, there is some debate over this point(15). Possibly citric acid might affect ketosis by effecting liver motabolism, primarily the Krebs cycle. Some individuals report that citric acid prevents them from entering ketosis but does not affect ketosis once it has been established. One study, examining very low-calorie diets, found that the consumption of citric acid inhibited ketosis and increased appetite in many individuals(16). Ultimately, individuals will have to determine for themselves whether citric acid or aspertame has any effect on ketosis, appetite or fatloss on a ketogenic diet.”
14. Gash At. Use of the traditional ketogenic diet for treatment of intractable epilepsy. JAm Diet Assoc (1990) 90:1433-1434.
15. Brunett A. Should diet soft driniks be restricted on a ketogenic diet[Letter]. J Am Diet Assoc (1991) 91:776.
16. Krietman S. Factors influencing body composition during very low-calorie diets. Am J Clin Nutr (1992) 56 (suppl):217S-223S.
From Rainbow Minerals website:
"Although fruits yield citric acid and malic acid, these acids are oxidized by the body as part of its energy-production process."
My thoughts: So if the body is using citric acid for energy, maybe that detracts from using fat for energy first or instead, possibly affecting ketosis??