A guy in our office only drinks Diet Cola and about 40-50 oz. of it a day. He says it is not harmful because there is no sugar.

But he does drink it every day, and there is 76 mg of caffeine per 20 oz. I checked the food label and there is no protein and I would say no nutritional value at all. So I wanted to know if what he says makes any sense, is it really not harmful? –Gary 

I would say that for someone to drink only 40-50 fl. oz. of diet cola daily is a bad idea.  A) No way is 50 fl. oz. sufficient fluid intake, and  B) Exclusively drinking diet colas isn’t a smart health move (unless that’s his only beverage and he is lost at sea or in the desert).  He’s right that they don’t contain sugar, but they do have artificial sweeteners.  Because they aren’t natural, I recommend no more than 3 servings a day of artificial sweeteners from any source. Perhaps switching from regular soda to diet is a big step for him!  The caffeine is not an issue. – Debbie J., MS, RD

Do you have a question about your diet or nutrition? Ask our dietitian by submitting your question to nutrition@lafitness.com or simply ask it in the COMMENTS section below.

To learn how to follow the “Ask Our Dietitian” Q&A CLICK HERE!