Most weight loss diets restrict carbohydrates, because too much of the energy-yielding nutrient leads to excess body fat. Many weight loss diets also seek to restrict fats and oils, partially due to a misconception that fat in the diet leads to fat on the body, and partially because fats and oils are also energy-yielding nutrients. Virtually no weight loss diets, however, restrict protein. Most people who follow the basic western diet get more protein than they need, many people following crash diets eat virtually nothing else, and many people who care about their health but not their weight or figure put themselves on diets that leave them without enough protein. No matter what the goal of a diet is, protein should be an important part of it, but where it comes from is important too.
Protein in the low-carb diet
Like the other macro nutrients — carbohydrates and fats – protein is an energy-yielding nutrient, though it yields the lowest amount of energy per gram. This is why high-protein foods – meats and some nuts – are just about the only thing allowed for people on some crash diets.
Animal sources of protein, especially red meat, are excellent sources of iron and other minerals, as well as protein, but red meat can also be a very high source of saturated fats, which can collect in the blood and cause heart problems, as well as weight gain, if eaten in high enough quantities. People on high-protein diets should consider going for white meat and fish more often, as well as trimming extra fat off of steaks and going for leaner ground beef and pork. Grilling rather than pan-frying can also reduce the consumed fat without cutting the protein of steak, burgers, and pork chops.
People on high-protein diets should also consider adding more proteins from plant sources, especially nuts and seeds. Many plant-sources of protein like beans have very high levels of protein, but also fairly high levels of carbohydrates, while most nuts have high protein and virtually no carbs. Plant sources of protein are also very high in fiber, which can be lacking from an all-meat diet sometimes leading to gastro-intestinal problems. If that weren’t enough reason, nuts and seeds are high in unsaturated fats (the good kind of fat) which is fairly low in most meats, with fish being a notable exception.
Cheese is another virtually carb-free food that supplies some protein, if not as much as meet. Cheese is also a good source of minerals like calcium that are low in meat products.
In addition to risking deficiencies of vitamins, minerals, oils, and fiber, eating a disproportionate amount of protein can lead to the body burning protein rather than carbohydrates, which can make the body acidic, and in some cases cause damage to the kidneys and heart.
Protein in Semitarian, or Ovo-lacto diets
On the other end of the spectrum, whether for health or personal reasons, many people are drastically reducing the protein that they take in from animal sources. Many of those who are swearing off of animal products for health reasons should consider changing the kind of meat that they eat, rather than cutting meat all together.
Many people who try to cut meat are really trying to cut out saturated fat, or growth hormones and antibiotics that are given to the animals to make them larger. Saturated fat can be cut out by eating more fish and chicken – chicken without the skin – and eating less pork and beef. As for growth hormones and antibiotics, these can be present in all kinds of meat (except fish).
Labelling on packaging that states that meat products are “organic” or free of hormones and antibiotics are all regulated by government agencies and fairly reliable. Furthermore, meat products like this are becoming easier to find and cheaper to purchase as more people become aware of potential health concerns from added antibiotics and hormones. Those swearing off of meat for ethical reasons should be a little more careful, however, as statements like “cage-free” are not as closely regulated, and are not as trustworthy.
Protein in Vegan diets
Those who are still sold on animal-free diets, weather for health or other concerns will still need all of the vitamins, minerals and nutrients that most people get primarily from meat. Protein is the first concern, although it shouldn’t be the main concern – remember, western diets tend to greatly exaggerate how much protein is actually needed.
Fortunately, protein is found in many plant-substances. Beans and nuts are usually the main source of protein for many people on animal-free diets, but seeds and grains – just about everything from wheat to rice — have protein as well. The proteins found in these sources is usually “incomplete” protein. There are many kinds of proteins, and proteins are made up of several smaller building blocks. Meat sources get a lot of credit in the protein world because they contain “complete” proteins that the body can use right away. The incomplete proteins that come from non-meat sources, when eaten in the right combinations, can be constructed by the body into the more complex proteins that are usually found in meat.
This has led to the idea of “complimentary proteins.” A lot of classic meal combinations from around the world, like beans and rice, are actually pairings of non-meat pairings that yield just the right incomplete proteins for the body to use to construct complete proteins. Those who are on a completely plant-based diet will be able to find several combinations of complimentary proteins by mixing and matching grains and nuts, nuts and seeds, grains and seeds, etc. Those who do not eat meat but allow themselves other animal products can experience far more variety, as dairy products can be thrown into the mix as well.
People following meat-free diets should be aware, however, that meatless diets tend to be higher in carbohydrates, which may actually make it easier to gain weight while following one. Plant-based protein sources with the fewest carbohydrates per serving are usually nuts and seeds (which are also great sources of healthy oils), while those with the most carbohydrates per serving are usually the grains.