Food is life. The quality of the food we eat directly correlates with our quality of life. Food provides the energy, building material, and essential nutrients our bodies need to carry out millions of physiological functions everyday.
In a general sense calories are used to measure food energy. Macronutrients-carbohydrates, proteins, and fats- compose a majority of the calories of the food that we consume.
Over the past few centuries, there has been much debate as to what ratio and quality of macronutrients is needed by the body to prevent many of the diet-related diseases predominant in America, which will prolong and provide for the highest quality of life. To put simply, there is no exact answer to this dilemma; each individual is unique and based on his or her genetics, family history, ethnicity, physical fitness goals and an array of other factors, will require different amounts and qualities of carbohydrates, fats, and proteins.
That being said, having a basic understanding of the functions of each of these macronutrients, as well as dietary recommendations composed by the United States Department of Agriculture, and the current debates surrounding these macronutrients, will allow you to make healthier and beneficial choices for your diet.
Protein: The Jack-of-All-Trades
What makes up a protein?
Second to water, protein is the highest component of the human body. It makes up approximately a fifth of our entire body weight and is essential to the function of every single cell in the human body. Proteins are composed of individual organic compounds called Amino Acids that bond together to form something called a polypeptide chain. The sequential makeup and three-dimensional shapes of these polypeptide chains determine what role the specific protein will have in the body. There are 20 amino acids that are combined in the body to make proteins, and of these 20 amino acids, 9 of them are considered essential and 11 are considered nonessential. An essential amino acid must be consumed in the diet as the body does not produce it in sufficient quantity, whereas, nonessential amino acids, though essential to the body, are produced in sufficient amounts by the body, and therefore does not need to be consumed in large quantities through the diet.
What are the different categories of protein?
Proteins are classified as being either complete or incomplete. A complete protein contains all 9 essential amino acids and promotes growth and health. Complete proteins can be found in eggs, fish, and milk. Incomplete proteins lack one or more essential amino acids or do not contain all essential amino acids in sufficient quantity. A protein can contain all 9 essential amino acids and still be incomplete if they are not present in equal proportion. Though individually incomplete proteins do not contain a sufficient amount of amino acids, combining various food sources of incomplete proteins can combine to form and have the same benefits of complete proteins. Some sources of incomplete proteins include grain, nuts, beans, and corn.
What are the Functions of Protein?
The function of protein goes beyond the commercially dairy advertised growth of muscle. Protein is responsible for building lean body mass. Proteins also function as enzymes, which carry out essential chemical reactions that take place in the cell. Some proteins, such as a large quantity and variety of hormones, act as messenger proteins transmitting responses throughout the body to coordinate biological processes between cells, tissues, and organs. Structural proteins provide structure and support for cells and on a larger scale allow the body to move. Finally, storage proteins bind and carry molecules throughout cells and the body.
Debate Time: Protein
There are many debates surrounding protein. Some more popular examples include, how much protein should one consume to gain muscle mass? Should I obtain my protein from animal or plant based foods? Will a high protein, low carb diet help me lose weight? There is no simple answer to anyone of these questions, because each individual is unique. However, there are a few rules of thumb when eating protein to help you sift through all these debates and come to a conclusion that best suits you.
First, the Dietary Guidelines for America, a reputable statement written jointly by U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA), recommends Americans consumes 10-35% of their daily caloric intake through protein. Protein contains 4 calories/gram. If one were to base this off a 2,000 calorie diet approximately 200-700 calories or about 50-175 grams of protein would be consumed daily. The percentage of calories can differ depending on the physical activity of the individual, someone who is highly active, or competes in a competitive sport would want to consume a higher amount of protein in their diet than someone who lives a more sedentary lifestyle.
Second, the Dietary Guidelines emphasizes three things variety, balance and moderation. Therefore in regards to whether to consume protein from plant based sources or animals, it is best to follow the principles of variety balance and moderation. Obtain protein from a variety of lean and white animal sources such as lean beef, chicken, fish, and eggs. However, also balance the amount of animal protein you eat with a variety of plant based proteins such as beans, lentils, tofu, and other soy products. Dairy is also an excellent source of protein. It is however important to note that the quality of protein consumed in lean meats tends to be higher and each meat has a higher ratio of complete proteins than do individual vegetables. In addition, over the last century there have been numerous studies providing evidence that consuming abundant amounts of animal based products correlates with increase risk for obesity, and heart disease. Whereas, vegetable based protein, though individually lacking in complete proteins, have the additional benefits of micronutrients (vitamins and minerals), as well as phytochemicals- chemicals found in plants that go beyond the plants basic nutrient components and have essential protective and disease preventative properties. There has been no significant evidence linking an abundance of vegetable based foods to a detrimental disease, consuming a large variety of vegetables is always a good thing. However, consuming a diet solely consisting of plant based products may cause certain nutrients such as protein to be insufficient and lead to complication such as fatigue, and detrimental complications especially in the elderly. Eat both a variety of plant and lean animal foods for protein, and do so without consuming an abundant amount, Eat a higher ratio of plant foods that animal foods, but do not neglect the importance of consuming sufficient quality and quantity of protein.
Finally, unless recommended by a Registered Dietitian, or Accredited Nutritional counselor always say no to any High-low diet. In the short term a high protein diet can help one lose weight. However, in the long term the diet can either lead to consuming insufficient quantities of other nutrients, and even a lack of weight loss. Other more severe consequences include High Blood pressure-which results from a large intake of meats and dairy, and is directly linked to heard disease, Kidney problems-as eating too much protein puts added stress on the kidneys for filtration, and Ketosis-which results from a lack of energy in the body due to inadequate carbohydrate intake and results in bad breath, fatigue, headaches sleeping problems and more.
Carbohydrates: The Power House Nutrient
What make up a carbohydrate?
Carbohydrates are the most abundant group of biological compounds on earth. Carbohydrates result as a byproduct of a process called photosynthesis that occurs in green plants. Carbohydrates are made up of the simplest form of a sugar known as a monosaccharide, and the product of two monosaccharide’s combined called disaccharides.
How are carbohydrates classified?
There are three main categories of carbohydrates significant to nutrition- Sugar, Starch, and Fiber.
Sugars, or simple carbohydrates are composed of one or two sugar molecules. A simple sugar is just as the name suggest, an example being the bag of white cane sugar in your sugar bowl. Other examples of simple sugars include soda, candy, and processed goods. Healthier examples include fruit, honey, and milk; they are healthier than the aforementioned because they contain vitamins and fiber. This makes them more nutrient-dense-containing a higher ratio of nutrients to calories, than Energy dense-having a higher ratio of calories to nutrients. Simple sugars are ingested quicker than complex carbohydrates.
Starches, or complex carbohydrates have three or more sugar molecules strung together like a necklace or branched like a coil. Complex carbohydrates are high sources of fiber, and therefore are associated with satiating hunger quicker than simple carbohydrates. Complex carbohydrates are generally found in whole plant foods such as green vegetables, whole grains-and foods made from them (oatmeal, whole-grain breads), Starchy vegetables (potatoes, sweet potatoes etc.), lentils, beans, and peas. The foods that fit under starches tend to be wholesome plant based foods, which mean they also have phytochemicals, as well as additional minerals and nutrients such as fiber.
Dietary Fiber (also known as roughage and bulk) contains pectin, cellulose and hemicellulose, which are found in whole grains, fruits, legumes, and vegetables. Dietary fiber includes all the parts of a plant that the body cannot digest or absorb, it instead stays intact and passes through the stomach, small intestine, colon and the proceeds out the body. Fibers bulk, and indigestibility aids in easing the process for the digestion of other food components preventing constipation. Fibers bulkiness also makes one feel full faster, and is directly linked to maintaining a healthy weight, and lowering one’s risk for obesity.
What are the functions of Carbohydrate?
Carbohydrate is the bodies preferred immediate energy source for all bodily functions, excluding protein in the use of building and repairing tissues. Carbohydrates contain 4 calories per gram. Carbohydrate performs the role of forming different lubricants in the body, and regulating fat metabolism. When consumed carbohydrates are broken down to produce glucose, a simple sugar. Glucose is broken down to produce heat and something called ATP (Adenine Triphosphate), ATP is then used as a source of Energy for the body. Excess carbohydrates not immediately broken down into glucose, are stored in the muscles and liver as glycogen. Muscle Glycogen can then be readily used as a source of energy for muscles during extraneous activity, whereas, glycogen in the liver can be released as glucose (blood sugar) and transported by the bloodstream. If muscle and liver glycogen storages are full, excess carbohydrate goes through a metabolic process called lipogenesis and is converted and stored as body fat.
Debate: Are Carbohydrates responsible for the increase of obesity and chronic disease in America?
At the turn of the century the nutritional recommendations to reduce fat intake changed completely to reducing carbohydrate intake. The new belief being that America is consuming an abundance of carbohydrates that is contributing to the momentous increase in obesity, cancer, heart disease, and diabetes in America.
However, this statement is misleading. While America has increased its intake of carbohydrates, it is not the macronutrient itself that should be held responsible for this increase in chronic disease in America. The rise in consumption of carbohydrates resulted as a result of food industries as well as food regulatory agencies targeting fat as the nutrient responsible for the rise of chronic disease in America. This lead to ill informed Americans to decrease their intake of fat only to increase their intake of carbohydrates. Not only did carbohydrate intake increase, but Americans also began to consume a higher ratio of simple carbohydrates. Fast food industries, processed foods, and other simple sugars became easily accessible and cheap to American workers always on the go looking for a quick meal.
Unlike complex carbohydrates and fiber, processed simple sugars are highly energy dense with relatively small vitamin and mineral profiles. These simple sugars simply packed on the calories, and neglected substantial vitamins and minerals. To worsen matter, simply sugars do not have the same immediate satiating affect as complex carbohydrates and fiber. Instead, it is very easy for someone to consume large amounts of simple sugar prior to feeling full, especially since portion sizes has increased drastically throughout fast food chains, and processed food industries. Finally, the fast food and processed food industry has responded to Americas demand to prevent vitamin and mineral deficiency by fortifying (adding a nutrient that did not exist in sufficient amounts) processed foods with nutrients, and decreasing the amount of fat content deeming the foods “healthier”. This prompted Americans to consume larger quantities of processed foods believing that they were now “healthy” and beneficial, when in reality many of these processed foods now contained higher sugar and carbohydrate content to compensate for the decrease in other nutrients such as fat.
This being said, it is not the consumption of carbohydrates that has lead to the increase of chronic disease in America. In truth, it is not even solely the consumption of simple sugars that has lead to rise of chronic disease. The United Stated Department of Agriculture (USDA), and the Department of Health and Human Services (HHS) recommends that a majority of calories-45-60% be obtained through carbohydrates; this “macronutrient distribution range (AMDR) was based on decreasing risk of chronic disease and providing adequate intake of other nutrients” (USDA, Dietary reference intake for energy). However, the dilemma comes in when considering the source of the carbohydrates, and the physical activity of the individual. According to the USDA less than 25% of calories should come from simple/processed sugars. A majority of carbohydrates should be consumed through complex carbohydrates and fiber rich foods such as green leafy vegetables, grains, legumes, and whole grain breads. In addition someone living a sedentary lifestyle would need to consume less carbohydrates than someone who is more active.
Fat: The Underdog Nutrient
What makes up Fat?
What most of us understand as dietary fat is actually a subcategory of a much larger group known as Lipids. Lipids consist of Triglycerides (dietary/neutral fat), steroids, and cholesterol. Dietary Fat has been fighting an ongoing battle for decades. Although there are correlations between certain fats and an increased risk for developing heart disease and cancer; there are certain fats, under the category of unsaturated fats that are not only essential to the proper functioning of every human being; but are also linked to decreasing the risk of certain caners and diseases. Dietary fats and oils are composed of a series of fatty acids molecules bound to a glycerol backbone forming a compound called a Triglyceride.
Function of Dietary Fat
All fats, including saturated fats, play essential roles in the body. These roles include-providing a concentrated stored form of energy, transporting vitamins A, D, E, and K into the body, cushioning and protection essential organs in the body, serving as an insulator and preserving body heat, and acting as a precursor to other essential body compounds such as cholesterol.
What are the Main Forms of Dietary Fat?
There are three types of fats that differ from one another depending on how many double-carbon bonds are contained in its structure.
A saturated fat is a triglyceride fat molecule lacking any double bonds between carbon molecules, because they are saturated with hydrogen molecules. The abundance of tightly linked hydrogen bonds in saturated fats makes most of them solid at room temperatures. A majority of saturated fat is found in animal products including meat and dairy; examples of saturated fat include-Poultry with skin, fatty beef, lamb, pork, lard and cream, butter, milk, and hard cheeses. Other high sources of saturated fat include baked goods, fried foods, and certain plant based oils-palm oil, palm-kernel oil, and coconut oil.
Unsaturated fats actually consist of two sub-categories of essential fatty acids (remember-anything referred to as an essential nutrient means it must be consumed in the diet, since the body does not produce it in sufficient amounts.) All Unsaturated fats contain double-carbon bonds, and are generally liquid at room temperature. Unsaturated fats are found in small amounts in lean meats and are abundantly found in fish, certain plant oils, seeds, and nuts.
Monounsaturated fats (MUFA’s) are unsaturated fat molecules containing only one double-carbon bond in its structure.
Polyunsaturated fats (PUFA’s) are unsaturated fat molecules containing two or more double-carbon bonds in its structure. A specific type of Polyunsaturated fat called Omega-3’s appears to decrease the risk of coronary artery disease, protect against irregular heart beat, and may help in lowering blood pressure levels. Omega 3’s are found in plant foods, however, plant based Omega-3’s are not as efficiently utilized by the body as Omega-3’s found in fish. Other essential, and beneficial polyunsaturated fats include Omega-6 and Omega-9 fatty acids.
The final form of dietary fats include Trans fat- a monounsaturated fat that is a contaminant byproduct of a process known as hydrogenation. Hydrogenation is a process used by food manufactures to add hydrogen atoms to vegetable oils, ultimately resulting in trans fats that mimic the properties of saturated, ultimately with the goal of increasing shelf life and longevity.
Debate Time: Is Fat Bad for You?
Starting in the 1980’s there began a massive launch by major food corporations and regulatory agencies to blame fat as the primary nutrient responsible for the rapid increase in obesity, and other nutrition related illnesses. The intended goal was to target saturated fat, which when consumed in access, has been linked to chronic illness, specifically coronary artery disease. However, due to the belief that it would be too complicated to explain the differences between the different types of fats, as well as pressures placed on government diet regulatory agencies by food industries, it was decided that if Americans were to simply reduce total fat consumption in their diet they would ultimately improve it, and reduce risk of coronary heart disease. We now know that eliminating fat from the diet cannot only increase the risk of obesity, but can also lead to vitamin deficiencies, Extreme mental fatigue, Amenorrhea in women, and other detrimental affects.
To understand how consuming fat can lead to chronic illness, you must first have a brief understanding of what cholesterol is and its role in the body.
Cholesterol is a lipid found in the livers of humans and other animals. Cholesterol is essential as it is needed to make vitamin D, all five steroid hormones, build cell walls, and create bile salts that aid in the digestion of fat.
If you were to hold cholesterol in your hand it would resemble a waxy thick white-yellow substance similar to candle shavings. Cholesterol flows in the body through the blood stream but its oily consistency does not mix well with the water like consistency of blood. In order for cholesterol to properly function and move smoothly throughout the bloodstream the body packages it into tiny protein covered particles called lipoproteins. Lipoproteins mix easily with blood and allow for the transportation of cholesterol and other lipids. The main lipoproteins are Low Density Lipid Proteins, and High Density Lipoproteins.
Low density Lipoproteins transfer cholesterol from liver throughout the body, where cells extract cholesterol and fat from them. Though essential, the higher fat to protein ratio of LDL lipoproteins makes them dangerous in abundance. When LDL is abundant in the bloodstream it forms fatty deposits in the walls of the coronary artery and other arteries. These deposits, known as plaque, narrows arteries and restrict blood flow. Build up, and release of plaque throughout arteries leads to strokes and heart attacks, and that is why LDL cholesterol is referred to as harmful cholesterol.
High Density Lipoproteins have a higher ratio of protein to fat content. They rummage the bloodstream for cholesterol deposited by LDL lipoproteins, and transport the cholesterol back to the liver for disposal, thus decreasing the risk of plaque build up and subsequently strokes, heart attacks and heart disease.
Fat is not bad for you, it is a very essential macronutrient in the body. However, consuming high levels of saturated and trans fat increases the level of LDL cholesterol in the blood, ultimately increasing the risk to developing coronary artery disease, heart disease, diabetes, and other related chronic illnesses. On the other hand, consuming a higher ratio of mono and poly unsaturated fats decreases the level of LDL cholesterol in the blood, reducing the risk for developing diseases associated with high blood lipids. A higher ratio HDL cholesterol is also associated with decreasing the effects of inflammation, stabilizing heart rhythms, improved quality of skin and hair and other health benefits.
A rule of thumb when it comes to consuming fat is to have most of your dietary fat come from white fish, plant-oils, nuts, and legumes; and to moderate the amount of beef, pork and other meat groups that promote high LDL cholesterol in the blood. In addition, trans fats should be avoided as much as possible as they increase inflammation, decrease HDL and increase LDL cholesterol levels, and are a risk factor for stroke, heart disease, diabetes and other chronic conditions.
The USDA’s dietary recommendation for fat intake is 20-35% of total daily calories. Fat contains 9 calories per gram. Eliminating fat for weight loss is not only debilitating for many biological processes but has also been linked to an increase risk for developing obesity. This is because people who tend to decrease fat content from the body tend to overcompensate by consuming processed sugars and high amount of simple carbohydrates, which when consumed in abundance increase fat deposits and blood pressure.
Proteins, Dietary Fats, and Carbohydrates are all essential to proper function and health of the human body. Just as every other nutrient in your body, they each play specific roles such as regulating chemical processes, supporting and protecting vital organs and, providing a source of energy. Excluding trans fats, none of these nutrients are solely responsible for contributing to the increase of chronic disease in America. The increase of chronic disease in America, specifically obesity, has resulted from an imbalance between physical activity and diet. Although other factor play a role such as genetics and environment, it is simply the over consumption of processed, energy dense foods combined with a lack of meaningful physical activity that has contributed to the drastic rise of chronic disease in America, not the individual macronutrients themselves.