DIET DOCTOR #9 - Printer Friendly - Muscle & Fitness Hers

DIET DOCTOR #9

Should you use soy instead of whey?

Q: I've always used soy protein, but after hearing about all the benefits of whey in your magazine I wonder if I am missing out by using soy instead of whey. Should I switch to whey around workouts?

A: No, I don't recommend replacing your soy with whey. Soy makes a great protein shake around workout time for numerous reasons. For starters, it is a fairly fast-digesting protein, which is good around workouts for getting the amino acids from the protein shake to your muscles ASAP. This allows for better energy during the workout and for better recovery after. Soy also has been found to boost nitric oxide (NO) levels. NO widens blood vessels so that more blood flows through them and to your muscles, which can help to deliver more nutrients and oxygen to your muscles, for even greater energy during the workout and to further benefit recovery after. Speaking of recovery, soy has been shown in several studies to enhance recovery following workouts better than whey protein. If that weren't enough, a new study has found that soy protein also boosts growth hormone levels (GH) in females. GH is an anabolic hormone that is especially important for females for making gains in muscle strength and muscle development, as well as encouraging fat loss. That's because women have low levels of the anabolic hormone, testosterone that men rely on for a good deal of their muscle strength and development. As good as soy is, I do suggest you add some whey to your pre and postworkout shakes, as whey will further boost the benefits of soy. Whey is even faster than soy, when it comes to its digestion rate, so it helps to boost energy levels during the workout and recovery after the workout, even further. Whey also increases blood flow to your muscles by a method different from NO. This means it can have an additive effect on blood flow when consumed with soy protein, which means even greater energy and recovery. And whey is rich in branched-chain amino acids (BCAAs). These amino acids can be used by the muscles for fuel, further boosting energy levels. Plus they're critical for instigating protein synthesis, which is science-speak for the process responsible for muscle recovery, growth and strength adaptations. For preworkout shakes shoot for about 10 grams of soy protein and 10 grams of whey protein within 30 minutes before workouts. For postworkout shakes, go with about 10-20 grams of soy and 10-20 grams of whey within 30 minutes after workouts.

To learn more about these protein powders, as well as another protein powder you may want to consider using, watch Jim's M&F Raw! Nutrition #2 - Postworkout Protein Trio video at muscleandfitness.com.