Sure, you know that protein is key to building muscle and staying lean, and you make a point to get enough daily. But, believe it or not, a review out of Canada of recent studies shows that you may still not be getting enough protein. If you're aiming for the low end of what's typically recommended which is .8g/kg of bodyweight. For a 180-lb guy that works out to a mere 66g of protein a day. Up that to 1g/kg (which is more in line with recommendations for fit guys) and you get about 82g of protein a day.

That's still not enough, according to the study. The data confirmed that higher protein diets help with weight-loss efforts, finding that subjects saw the best results with a diet of about 25% protein. They suggest 25-35g of protein per meal, which works out to 75-105g in a day—before any snacks.

What's more: It's not just about how much you get in a day; timing is important too. Spreading out your protein intake during the day allows for muscle synthesis to continue over a 24-hour cycle, so your body never stops maintaining its muscles. That means no more bagel-and-cream-cheese breakfasts, no matter how much chicken you plan to scarf at dinner. (And if you're like the average American guy, dinner is where you get the biggest dose of protein, according to a chart in the study.)

But don't worry—getting more protein into each meal isn't hard. Here are some of the best sources to get you started. If you're really trying to lose weight and put on muscle, you'll want even more than 105g of protein in your day. Check out the Men's Fitness Food Pyramid for more info.

Study Methodology: Previous data concerning protein intake has been based on the nitrogen balance method, which many scientists see as a limited approach based on systematic over- and under-estimations. The research used in the review, published in Canada’s NRC Research Press, is based on a stable isotope method that provides more accurate results.