Proteins are essential nutrients for the human body. They are one of the building blocks of body tissue, and can also serve as a fuel source. As fuel, proteins contain 4 kcal per gram, just like carbohydrates and unlike lipids, which contain 9 kcal per gram. Proteins are polymer chains made of amino acids linked together by peptide bonds. In nutrition, proteins are broken down in the stomach during digestion by enzymes known as proteases into smaller polypeptides to provide amino acids for the body, including the essential amino acids that cannot be biosynthesized by the body itself. Amino acids can be divided into three categories: essential amino acids, non-essential amino acids and conditional amino acids. Essential amino acids cannot be made by the body, and must be supplied by food. Non-essential amino acids are made by the body from essential amino acids or in the normal breakdown of proteins. Conditional amino acids are usually not essential, except in times of illness, stress or for someone challenged with a lifelong medical condition. Essential amino acids are leucine, isoleucine, valine, lysine, threonine, tryptophan, methionine, phenylalanine and histidine. Non-essential amino acids include alanine, asparagine, aspartic acid and glutamic acid. Conditional amino acids include arginine, cysteine, glutamine, glycine, proline, serine, and tyrosine. The amount of protein we need on a daily basis is 0.75-1g per kg of body weight, so a 60 kg person would need 45-60g of protein a day. To put this in perspective 100g meat has around 20g protein, so if you have 100g meat for lunch and 125 g meat at dinner this is 45g protein just in your meat, not including all the other protein sources you are eating! If you are on a low carb diet you could up your protein a little but is better to up your fat instead. Remembering that protein and fat can be used to make glucose which is the fuel source for your body. Protein can still promote an insulin response as well as carbs do, but to a lesser degree, so this is why I prefer fat as my energy source. Fat does not make you fat...sugar does! Here are some non- meat sources of protein chickpeas 7g protein /100g ABC spread 3.7g /20g burgen rye bread 9.5g /2 slices baked beans 10.6g/ 220g can full cream milk 8.3g /250ml egg 6g /1 egg all this adds up to 45.1 g protein, so as you see it is pretty easy to get all the protein you need if you are vegetarian.
Posted on: Sun, 09 Jun 2013 01:18:11 +0000