Monday, September 25, 2006

Macronutrients. Protein

After water, the biggest component in the body is protein. Over 98% of the molecules in body are replaced every year. So we need protein as a building block. If we don't get enough protein, or if we are eating poor quality protein, our bodies will not grow strong muscles, bones, blood, teeth, etc.

There's no definitive answer how much protein do we really need. Every expert has a different opinion. Here are a few examples:

Let's start with sports nutrition expert Michael Colgan. His research suggests that the type of sport you do has an effect on the amount of protein you need. Strength sports people need approx 2.0 grams of protein per kg of bodyweight per day. Athletes who need speed first, then strength, then endurance need about 1.7 g/kg/day & endurance athletes need 1.4 g/kg/day.

This requirement is based on a high level of training, 3-4 hours a day. If you are only training 1-2 hours a day, your requirement will be less, by approx 0.3 g/kg/day. For an 80 kg man doing 1-2 hours riding a day, this would be 80 x 1.1g = 88 g per day. Doing 3-4 hours riding, he would need 80 x 1.4g = 112 g. These are his rough guidelines only, each person will have different individual needs.

The Zone's Barry Sears multiplies your lean body mass in lbs by a sliding scale ranging from 0.5 for couch potatoes, to 1.0 for very heavy training. Say our 80 kg cyclist has a fat % of 20%. That means his lean body mass is 64 kg (or approx 140 lbs). He would come into the 0.8 category, so would need 140 x 0.8 = 112 grams. However a very fit lean cyclist of the same weight with only 15% body fat, & a higher lean body mass, would need 120 grams.

The range we're talking about is slightly higher than Colgan, but depends on lean body mass, rather than weight. The other main difference is that the amount of protein, once calculated, must be strictly adhered to "to get into the Zone", and determines the amount of carbs & fat you can eat.

Eat Right 4 Your Blood Type diet's Peter D'adamo recommends different ratios for each blood type. His rough guidelines are 20% for A & AB, 34% for B, and 45% for O types. The metabolic diets don't specify protein requirements in grams, but Hunter-Gatherers need animal protein at every meal, whereas extreme Agriculturists thrive on a vegetarian diet.

Traditional nutritionists will probably recommend 10-15% of calories. A lot of naturopathic nutritionists are concerned that the level of protein consumption is too high. I have seen recommendations ranging from .6g/kg/day to 1g/kg/day.

So who's right? The best way to determine your need for protein is to determine your metabolic type first. That will give you a good idea of how high your protein levels need to be. If you are trying out a particular diet regime, start within those guidelines. Otherwise, start with Michael Colgan's recommendations and see how you feel. It's fairly easy to tell if you're not getting enough protein - you will lose (or at least not gain) muscle mass and strength. You may find that your muscles take a long time to recover after exercise, or your energy levels might be very low. Try adding a little more protein to your diet and see if you improve.

It's harder to tell if you're getting too much. If you are drinking lots of water and are feeling fine, you're probably doing OK. If you eat excess protein to a level that your kidneys can't handle, you will start to get kidney pain and feel generally unwell. It may take a bit of trial and error to get the balance right for you.

The best protein

The first factor here is bioavailability. Michael Colgan ranks protein sources in this order :

ProteProtein sourcein source

Bioavailablility

Whey peptide blends

110-159

Whey concentrate (lactalbumin)

104

Whole egg

100

Cow's milk

91

Egg White (albumin)

88

Fish

83

Beef

80

Chicken

79

Casein

77

Soy

74

Rice

59

Wheat

54

Beans

49

But you also need to take into account how your body responds to each of these protein sources. Some people don't digest whey products particularly well, even high quality ones. Your metabolic type will determine which proteins sources suit you best.

Some athletes following a whole food diet find they have excellent muscle growth and recovery eating raw egg yolks or raw liver after workouts, for example.

My take on this is : eat a variety of different foods - the ones that work for you - and get your protein from as many different sources as possible. If you find that you're not getting enough protein from your normal diet, you can add in a supplement. But if you're on a strict whole foods diet, you may find you can't have any of them.

If you are aiming to eat 120grams of protein a day, you might want 30 grams 4 times a day. 30 grams of complete protein would come from approx:

  • 110-120 grams of lean meat or poultry

  • 150 grams of fish
  • 6 eggs
  • 1 cup of cottage cheese
  • 2-3 cups yoghurt
  • 1 "shake" made from microfiltered whey protein powder, or whey protein concentrate
  • try not to use soy as a major protein source

Nuts and seeds have some protein, but have at least 75% fat in them, so should be considered a fat source. Legumes and grains also have some protein, but are primarily a carbohydrate source. If you are following a vegetarian diet, you need to combine 2-3 of these 4 food groups at a meal to make complete protein. Some examples :

  • Whole grains, with nut milk and some sunflower seeds or ground flaxseed

  • Beans and rice
  • Corn tortilla with mexican beans
  • Hummus (chick peas and sesame paste) with whole grain pita breads
  • Tempeh with stir fried with rice and veges, with a handful of pumpkin seeds

It's good to have a a dollop of protein at breakfast, 20-30 grams if possible. This helps keep your blood sugar steady throughout the day. If you are taking a supplementary "shake", take it when your body needs easily digested protein most, either an hour or two before hard training, or straight after. Other than that, spread your protein intake evenly throughout the day, and aim to have at least some protein and fat with every meal or snack.

More: Macronutrients. Carbohydrates, Macronutrients. Fat (We Like It, Don't We?)

Protein