Signs you are not getting enough protein

But despite our national preoccupation with protein, some of us are still slipping through the cracks—namely vegetarians or people who tend to under-eat. Problem is, it can be tricky to identify what's considered "not enough" since the recommended intake of protein is a broad range, rather than one hard number. If somebody is eating a 2,000-calorie diet, it could be 50 grams to 150 grams of protein per day. (Things like activity level and weight influence where your ideal intake falls.)
 
Afraid you're short-changing your system? Forget crunching numbers—just look for these signs that your body is begging for protein:
 
You Crave Sweets
One of the first signs you're low on protein: You start craving sweets and feel like you're never quite full. You'd think a protein shortage would trigger an urge for steak and eggs, right? But one of protein's most critical functions is keeping your blood sugar steady—which means if you're lacking, your glucose levels will be all over the place, encouraging you to reach for a quick fix like candy. "If all you ate in the morning was a handful of cereal, you're going to get energy right away, then your energy is going to wane," she says. "That up-and-down is where cravings come in."
 
Your Brain Feels Foggy
Balanced blood sugar is essential for staying focused. So when you're protein-deprived and your glucose levels are fluctuating constantly, you may feel a little foggy—like you can't quite get with the program at work, for example. Why? Because you don't have a steady stream of carbs to fuel your brain. Protein at meals helps time-release the carbs for steady energy rather than up and down spikes. If you're relying only on "fleeting foods," such as crackers or bread, you'll only experience short bursts of mental energy, followed by the fog. 

Your Hair is Falling Out
Protein is the building block of all of your cells—your hair follicles included. "If your hair follicles are strong, they keep your hair on your head, despite the tugging we do all day and the wind going through your hair. But if you're chronically skimping on the scalp-stabilizing nutrient, you may notice that your strands start thinning (although, keep in mind, this can also be a sign of other conditions, like thyroid trouble).

You Feel Weak.
We all know that protein is essential for building muscle. And if you don't get enough of it, your muscles may start to shrink over time. As a result, you may feel weak and unable to do the exercises you once excelled at.
 
You Get Sick Constantly
Your biceps aren't the only thing that protein reinforces. Protein is needed to build all the compounds in our immune systems. So if you seem to catch colds or infections more often than everyone else—and you're otherwise in good health—a protein deficiency may be to blame. Another sign: You constantly get hangnails. "Our skin is a huge immune organ because it protects us from the environment," says Blatner. If your skin isn't strong due to a shortage of protein, you may start to notice cracks and tears (like hang nails), potentially exposing you to pathogens and leading to infections.