Although my personal experience is only a scientific study of one, consumers of protein shakes and energy bars should be aware that these convenient edibles can increase your risk for kidney disease and/or kidney stone formation.
Kidney stones are build-ups of calcium. Most pass through our urine without us knowing. But, if they expand to sizes of 2-3mm or more, get ready for some mean back pain, potential fever, possible nausea and hematuria (blood in urine).
After a recent battle with kidney stones, my urologist asked that I pee in a bottle and save my urine for a 24-hour period. Subsequent lab analysis revealed VERY high protein levels in my urine. Once he heard about my daily dose of an energy bar or two (or the occasional protein bar), he immediately blurted, "Cut those out." Turns out these health and energy bars contain high levels of protein that can actually contribute to kidney stone formation for people like me who eat them as between-meal snacks.
A quick look at the wrappers reveals:
ClifBar - 10g protein (20% of your recommended daily protein intake)
Balance Bar - 16g protein (30% of your recommended daily protein intake)
Promax Bar - 20g protein (a whopping 40% of your recommended protein intake)
Consuming that much protein may be okay for someone using one of these bars as a meal substitute, but I typically eat three square meals per day and there's almost always meat on my dish (fish, poultry, pork and occasionally beef).
A Chipotle Chicken Fajita Burrito, for example, contains 56grams of protein - that meal alone equals 105% of the RDA of protein (based upon a 2000 calorie daily diet). To be accurate, my daily diet is likely around 3000 calories as a result of my active lifestyle, but still that would mean 75grams is all the daily protein I need. One burrito and a Promax bar gets me to that level in a hurry.
What to do? It's my personal opinion that Gatorade and other sport drinks should be consumed only after sweaty workouts of 30 minutes or more. Similarly, energy bars are a great nutrition supplement to eat during a ride or immediately after a 60-minute or longer exercise session. But, to insert these processed foods into your regular daily diet is probably not healthy. Eat a banana or apple instead.