There are 14 non-essential amino acids. They are termed non-essential as they can be manufactured by the body and do not have to be derived from food. The body, on the other hand, cannot produce the remaining 8 essential amino acids itself, and therefore they must be derived from the food that we eat. Non-essential amino acids are just as important as essential amino acids, as without the other, new proteins that are needed by the body cannot be properly formed. It is therefore vital that a variety of foods are eaten in order to provide the body with all of the amino acids required.
OK, so that's the basic science behind protein. But there is much more to it. Why is it important when building muscle? Why is it so important when losing weight? Oh so many questions. And even more answers. Even the official answers on how much is enough vary depending on the source. The USDA says one thing while the World Health Organization says much less. Body builders are all about the protein and eat massive amounts of it. So why? Well, here's an attempt to answer that.
Some nutritionists, and the World Health Organization (W.H.O), believe the U.S.D.A standards are too high. The W.H.O recommends 8 grams of protein for every 20 lbs. for adults. By those standards, an adult woman weighing 130 lbs. would only need 52 grams of protein - less than half of what the U.S.D.A. suggests. An adult male of 180 lbs. would need 72 grams. Again, less than half. The discrepancies between the U.S.D.A and the W.H.O may reflect special interest pressures on those groups. At any rate, one might surmise that the U.S.D.A numbers are at the top end of any reasonable scale.
As a reference, the U.S.D.A offers the following guidelines as to what serving sizes equal an ounce of protein: "In general, 1 ounce of meat, poultry or fish, ¼ cup cooked beans, 1 egg, 1 tablespoon of peanut butter, or ½ ounce of nuts or seeds can be considered as 1 ounce equivalent from the Protein Foods Group."
However, many sports nutrition experts have concluded that protein requirements are higher for athletes(American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada (2000). Joint Position Statement: Nutrition and athletic performance. Med. Sci. Sports Exerc. 32:2130-2145).
The additional protein may be needed in order to promote muscle adaptation during recovery from exercise in several ways:
- Aiding in the repair of exercise-induced damage to muscle fibers.
- Promoting training-induced adaptations in muscle fibers (e.g., synthesis of new proteins that are involved in energy production and/or force generation).
- Facilitating the replenishment of depleted energy stores.
- Protein recommendations for endurance athletes are 1.2 to 1.4 g per kilogram of body weight per day, whereas those for resistance and strength-trained athletes may be as high as 1.6 to 1.7 g per kilogram of body weight per day.
Studies (Tipton KD, Wolfe RR. (2004). Protein and amino acids for athletes. J Sports Sci. 22:65-79; Rasmussen RB, Phillips SM. (2003). Contractile and nutritional regulation of human muscle growth. Exerc. Sport Sci. Rev. 31:127-131.) have shown:
The amount of dietary protein needed to stimulate muscle recovery is surprisingly small, only 5 to 10 grams of amino acids (that's only 20 to 40 kcal of protein).
Essential amino acids are superior to non-essential amino acids for stimulating muscle growth. Foods such as fish, meat, eggs, and milk are rich in essential amino acids.
The "maximum effective dose" of amino acids (i.e., the single serving size that will maximally stimulate muscle protein accretion) is not known, however, one study showed that the amount of muscle protein gained was similar when subjects consumed 20 to 40 g of essential amino acids after weightlifting exercise. (Tipton KD, Ferrando AA, Phillips SM, Doyle D Jr, Wolfe RR. (1999). Postexercise net protein synthesis in human muscle from orally administered amino acids. Am J Physiol Endocrinol Metab 276:E628-E634.)
Thus, there seems to be a point of amino acid availability above which no further stimulation of muscle protein synthesis occurs. This suggests that consuming massive single doses of protein in hopes of further accelerating muscle growth (as often practiced by strength athletes) is futile.
The anabolic boost stimulated by a single dose of amino acids is transient and lasts only one to two hours. This means that ingesting repeated small doses of protein during recovery may be more effective in optimizing the rate of muscle protein gain, as opposed to eating just one large meal.
Carbohydrate added to a protein mixture does not markedly affect the muscle anabolic response, but does confer other benefits, most important being the resynthesis of muscle glycogen.
Two studies recently reported that consuming a protein and carbohydrate beverage during exercise increased performance as compared to carbohydrate alone. ( Ivy JL et al. (2003). Effect of a carbohydrate-protein supplement on endurance performance during exercise of varying intensity. Int J Sports Nutr Exerc Metab. 13:382-395; Saunders MJ et al. (2004). Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage. Med Sci Sports Exerc. 36:1233-1238.)
Both studies measured exercise time to fatigue in trained cyclists using a randomized double-blind repeated measures design. In each experiment, subjects ingested a 7.75 percent carbohydrate solution on one occasion and a drink that contained 7.75 percent carbohydrate plus an additional 1.94 percent protein (about 4 g of protein per 8-oz serving) on another occasion.
Results
In the first study, subjects cycled at 85 percent peak VO2max immediately after performing three hours of standardized cycle exercise. Results showed that the subjects:
- Rode 36 percent longer when ingesting the carbohydrate solution as compared to the placebo.
- Rode 55 percent longer when ingesting the carbohydrate + protein solution compared to placebo, and this was also significantly longer than the carbohydrate trial.
Eggs are the best source of protein as they contain the highest amount of essential amino acids. Fish is the next best source and is then followed by meat, milk, cereal eaten with pulses, soya beans, oatmeal, rice, peas, lentils, kidney beans and then wholemeal bread.
Try to consume a variety of protein-rich foods, including pulses, fish, vegetables, shellfish and lean meat, rather than just red meat or only dairy products, as some foods that contain high amounts of protein also contain high levels of saturated fat, which is extremely bad for the body.
It is also advisable to swap full-fat foods or foods that are high in saturated fats, for a low-fat version, for example change cheddar cheese to cottage cheese and full-fat milk to semi-skimmed or skimmed milk.
To help you make lower-fat protein choices —
- Choose meats that are leaner cuts and trim away any fat you can see. For chicken and turkey, remove the skin to reduce fat.
- Substitute pinto or black beans for meat in chili and tacos.
- Choose low-fat or fat-free milk and yogurt.
- Choose low-fat or fat-free cheese.
- Choose egg whites or pasteurized egg white products.
Tips for Vegetarians
- Build meals around protein sources that are naturally low in fat, such as beans, lentils, and rice. Don't overload meals with high-fat cheeses to replace the meat.
- Calcium-fortified soymilk provides calcium in amounts similar to milk. It is usually low in fat and does not contain cholesterol.
- Many foods that typically contain meat or poultry can be made vegetarian. This can increase vegetable intake and cut saturated fat and cholesterol intake. Consider:
- pasta primavera or pasta with marinara or pesto sauce
- veggie pizza
- vegetable lasagna
- tofu-vegetable stir fry
- vegetable lo mein
- vegetable kabobs
- bean burritos or tacos
- A variety of vegetarian products look (and may taste) like their non-vegetarian counterparts, but are usually lower in saturated fat and contain no cholesterol.
- For breakfast, try soy-based sausage patties or links.
- Rather than hamburgers, try veggie burgers. A variety of kinds are available, made with soy beans, vegetables, and/or rice.
- Add vegetarian meat substitutes to soups and stews to boost protein without adding saturated fat or cholesterol. These include tempeh (cultured soybeans with a chewy texture), tofu, or wheat gluten (seitan).
- For barbecues, try veggie burgers, soy hot dogs, marinated tofu or tempeh, and veggie kabobs.
- Make bean burgers, lentil burgers, or pita halves with falafel (spicy ground chick pea patties).
- Some restaurants offer soy options (texturized vegetable protein) as a substitute for meat, and soy cheese as a substitute for regular cheese.
- Most restaurants can accommodate vegetarian modifications to menu items by substituting meatless sauces, omitting meat from stir-fries, and adding vegetables or pasta in place of meat. These substitutions are more likely to be available at restaurants that make food to order.
- Many Asian and Indian restaurants offer a varied selection of vegetarian dishes.
Although the body needs a certain amount of protein, too much can be harmful for a person's health.
There is a significant risk of high cholesterol, due to the high amount of saturated fats in certain foods, which could in turn lead to heart disease and stroke.
Too much protein also puts a strain on the liver and kidneys. Foods that contain protein have high levels of nitrogen, which are harmful to the body and must be eliminated. The role of the kidneys is to filter out waste products and therefore an excess of protein will force the kidneys to work harder to remove the nitrogen waste from the body. This stress could ultimately lead to kidney disorders or damage to the body's filtering capacities.
Due to the inability of the body to store excess protein, any surplus protein that is consumed is then converted into glucose in the liver and either used up as energy or stored as fat.
Some protein-rich foods are high in nucleic acids, which when broken down, are converted into uric acid. Consequently, too much uric acid in the blood can lead to gout, an extremely uncomfortable condition that causes a person's joints to become inflamed, tender and agonizingly painful to move.
Finally, too much protein in the diet could also lead to osteoporosis (thinning of the bones), as an excess of protein promotes the loss of calcium in the bones through urine.
There is a significant risk of high cholesterol, due to the high amount of saturated fats in certain foods, which could in turn lead to heart disease and stroke.
Too much protein also puts a strain on the liver and kidneys. Foods that contain protein have high levels of nitrogen, which are harmful to the body and must be eliminated. The role of the kidneys is to filter out waste products and therefore an excess of protein will force the kidneys to work harder to remove the nitrogen waste from the body. This stress could ultimately lead to kidney disorders or damage to the body's filtering capacities.
Due to the inability of the body to store excess protein, any surplus protein that is consumed is then converted into glucose in the liver and either used up as energy or stored as fat.
Some protein-rich foods are high in nucleic acids, which when broken down, are converted into uric acid. Consequently, too much uric acid in the blood can lead to gout, an extremely uncomfortable condition that causes a person's joints to become inflamed, tender and agonizingly painful to move.
Finally, too much protein in the diet could also lead to osteoporosis (thinning of the bones), as an excess of protein promotes the loss of calcium in the bones through urine.
So you may be wondering at this point what all the high protein hype is about and if it's really all it's cracked up to be. Well, again, opinions range on that.
Participants in a study published in the American Journal of Clinical Nutrition reported greater satisfaction, less hunger, and weight loss when fat was reduced to 20% of the total calories in their diets, protein was increased to 30%, and carbs accounted for 50%. The study participants ate some 441 fewer calories a day when they followed this high-protein diet and regulated their own calorie intake.
Another study, reported in the Journal of Nutrition, showed that a high-protein diet combined with exercise enhanced weight and fat loss and improved blood fat levels. Researchers suggest that higher-protein diets help people better control their appetites and calorie intake.
Diets higher in protein and moderate in carbs, along with a lifestyle of regular exercise are often purported by experts to reduce blood fats and maintain lean tissue while burning fat for fuel without dieters being sidetracked with constant hunger.
Researchers don't understand exactly how protein works to turn down appetite. They surmise that it may be because a high-protein diet causes the brain to receive lower levels of appetite-stimulating hormones. It may be due to eating fewer carbs and/or the specific protein effect on hunger hormones and brain chemistry.
Another study, reported in the Journal of Nutrition, showed that a high-protein diet combined with exercise enhanced weight and fat loss and improved blood fat levels. Researchers suggest that higher-protein diets help people better control their appetites and calorie intake.
Diets higher in protein and moderate in carbs, along with a lifestyle of regular exercise are often purported by experts to reduce blood fats and maintain lean tissue while burning fat for fuel without dieters being sidetracked with constant hunger.
Researchers don't understand exactly how protein works to turn down appetite. They surmise that it may be because a high-protein diet causes the brain to receive lower levels of appetite-stimulating hormones. It may be due to eating fewer carbs and/or the specific protein effect on hunger hormones and brain chemistry.
The American Heart Association has this to say about diets high in protein:
Most Americans already eat more protein than their bodies need. And eating too much protein can increase health risks. High-protein animal foods are usually also high in saturated fat. Eating large amounts of high-fat foods for a sustained period raises the risk of coronary heart disease, diabetes, stroke and several types of cancer. People who can't use excess protein effectively may be at higher risk of kidney and liver disorders, and osteoporosis.
That's why the American Heart Association guidelines urge adults who are trying to lose weight and keep it off to eat no more than 35 percent of total daily calories from fat and less than 7 percent of total daily calories from saturated fat and less than 1 percent of total daily calories from trans fat. On most high-protein diets, meeting these goals isn't possible.
Some high-protein diets de-emphasize high-carbohydrate, high-fiber plant foods. These foods help lower cholesterol when eaten as part of a nutritionally balanced diet. Reducing consumption of these foods usually means other, higher-fat foods are eaten instead. This raises cholesterol levels even more and increases cardiovascular risk.
High-protein diets don't provide some essential vitamins, minerals, fiber and other nutritional elements. A high-carbohydrate diet that includes fruits, vegetables, nonfat dairy products and whole grains also has been shown to reduce blood pressure. Thus, limiting these foods may raise blood pressure by reducing the intake of calcium, potassium and magnesium while simultaneously increasing sodium intake.
So I suppose, like most things, it really depends on who you ask and what your lifestyle is. I think the best plan is balance, but that's not always possible. And I do personally find that protein keeps me full much longer than most other things I eat. Though I am learning more about dietary fiber and the benefits it provides in overall health and also in feeling satisfied longer. But that's for another blog.
In general, 1 ounce of meat, poultry or fish, ¼ cup cooked beans, 1 egg, 1 tablespoon of peanut
butter, or ½ ounce of nuts or seeds can be considered as 1 ounce equivalent from the Protein
Foods Group.
The chart lists specific amounts that count as 1 ounce equivalent in the Protein Foods Group
towards your daily recommended intake:
Some good protein sources:
What counts as an ounce equivalent in the Protein Foods Group?
In general, 1 ounce of meat, poultry or fish, ¼ cup cooked beans, 1 egg, 1 tablespoon of peanut
butter, or ½ ounce of nuts or seeds can be considered as 1 ounce equivalent from the Protein
Foods Group.
The chart lists specific amounts that count as 1 ounce equivalent in the Protein Foods Group
towards your daily recommended intake:
Amount that counts as 1 ounce equivalent in the Protein Foods Group
|
Common portions and ounce equivalents
| |||
|---|---|---|---|---|
Meats
|
1 ounce cooked lean beef
|
1 small steak (eye of round, filet) = 3½ to 4 ounce equivalents
| ||
1 ounce cooked lean pork or ham
|
1 small lean hamburger =
2 to 3 ounce equivalents | |||
 | ||||
Poultry
|
1 ounce cooked chicken or turkey,
without skin |
1 small chicken breast half =
3 ounce equivalents | ||
1 sandwich slice of turkey
(4 ½ x 2 ½ x 1/8”) |
½ Cornish game hen =
4 ounce equivalents | |||
| ||||
Seafood
|
1 ounce cooked fish or shell fish
|
1 can of tuna, drained =
3 to 4 ounce equivalents 1 salmon steak = 4 to 6 ounce equivalents 1 small trout = 3 ounce equivalents | ||
| ||||
Eggs
|
1 egg
| 3 egg whites = 2 ounce equivalents 3 egg yolks = 1 ounce equivalent | ||
| ||||
Nuts and seeds
|
½ ounce of nuts (12 almonds, 24 pistachios, 7 walnut halves)
½ ounce of seeds (pumpkin, sunflower or squash seeds, hulled, roasted) 1 Tablespoon of peanut butter or almond butter |
1 ounce of nuts or seeds =
2 ounce equivalents | ||
| ||||
¼ cup of cooked beans (such as black, kidney, pinto, or white beans)
¼ cup of cooked peas (such as chickpeas, cowpeas, lentils, or split peas) ¼ cup of baked beans, refried beans |
1 cup split pea soup =
2 ounce equivalents 1 cup lentil soup = 2 ounce equivalents 1 cup bean soup = 2 ounce equivalents | |||
¼ cup (about 2 ounces) of tofu
1 oz. tempeh, cooked ¼ cup roasted soybeans 1 falafel patty (2 ¼”, 4 oz) 2 Tablespoons hummus |
1 soy or bean burger patty =
2 ounce equivalents | |||
Some good protein sources:
Beef
- Hamburger patty, 4 oz – 28 grams proteinSteak, 6 oz – 42 grams
- Most cuts of beef – 7 grams of protein per ounce
- Chicken breast, 3.5 oz - 30 grams protein
- Chicken thigh – 10 grams (for average size)
- Drumstick – 11 grams
- Wing – 6 grams
- Chicken meat, cooked, 4 oz – 35 grams
- Most fish fillets or steaks are about 22 grams of protein for 3 ½ oz (100 grams) of cooked fish, or 6 grams per ounce
- Tuna, 6 oz can - 40 grams of protein
- Pork chop, average - 22 grams protein
- Pork loin or tenderloin, 4 oz – 29 grams
- Ham, 3 oz serving – 19 grams
- Ground pork, 1 oz raw – 5 grams; 3 oz cooked – 22 grams
- Bacon, 1 slice – 3 grams
- Canadian-style bacon (back bacon), slice – 5 – 6 grams
- Egg, large - 6 grams protein
- Milk, 1 cup - 8 grams
- Cottage cheese, ½ cup - 15 grams
- Yogurt, 1 cup – usually 8-12 grams, check label
- Soft cheeses (Mozzarella, Brie, Camembert) – 6 grams per oz
- Medium cheeses (Cheddar, Swiss) – 7 or 8 grams per oz
- Hard cheeses (Parmesan) – 10 grams per oz
- Tofu, ½ cup 20 grams protein
- Tofu, 1 oz, 2.3 grams
- Soy milk, 1 cup - 6 -10 grams
- Most beans (black, pinto, lentils, etc) about 7-10 grams protein per half cup of cooked beans
- Soy beans, ½ cup cooked – 14 grams protein
- Split peas, ½ cup cooked – 8 grams
- Peanut butter, 2 Tablespoons - 8 grams protein
- Almonds, ¼ cup – 8 grams
- Peanuts, ¼ cup – 9 grams
- Cashews, ¼ cup – 5 grams
- Pecans, ¼ cup – 2.5 grams
- Sunflower seeds, ¼ cup – 6 grams
- Pumpkin seeds, ¼ cup – 8 grams
- Flax seeds – ¼ cup – 8 gramsSources:
SOURCES
- http://pilates.about.com/od/pilatesandweightloss/a/What-Is-Protein.htm
- http://www.active.com/nutrition/Articles/The_role_of_protein_in_exercise_recovery.htm
- http://www.helpwithcooking.com/nutrition-information/protein-guide.html
- http://www.cdc.gov/nutrition/everyone/basics/protein.html
- http://www.choosemyplate.gov/healthy-eating-tips/tips-for-vegetarian.html
- http://lowcarbdiets.about.com/od/whattoeat/a/highproteinfood.htm
- http://www.webmd.com/diet/guide/high-protein-diet-weight-loss
- http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/High-Protein-Diets_UCM_305989_Article.jsp
No comments:
Post a Comment