By Andrea Holwegner, Health Stand Nutrition Consulting Inc.
With an overwhelming load of nutrition information in books, on the internet, and through media, it is hard to know what is reliable information. Recently the debate between carbohydrate and protein balance has bombarded discussions on nutrition. You may be wondering “Do eating carbohydrates make you gain weight? Should I follow a high protein, low carbohydrate diet? What is insulin and the glycemic index?” Read on to find out more…
Functions of Carbohydrates and Protein
It is first useful to review the function of protein and carbohydrate from food. Protein is found in meats, fish, poultry, dairy foods, nuts/seeds, eggs, and beans/legumes. The role of protein in the body is for structure and repair of tissues, production of antibodies to fight infection, to act as oxygen carrier molecules, and for enzymes for body reactions. The consequences of not eating enough protein include poor repair of muscle and other body tissue, weakened immune system, and increased risk of osteoporosis and bone fractures. Not consuming enough protein will also likely result in poor concentration, poor blood sugar control, and frequent hunger and cravings. This is because protein helps to slow down digestion of food thereby slowing the rate that carbohydrates (sugar) enter the blood stream.
Carbohydrates are found in grains (such as pasta, rice and bread), as well as fruits, vegetables, milk, yogurt, beans/legumes, and sweets (such as pop, candy, and desserts). The carbohydrate family includes simple sugars, starches, and dietary fiber. The types of carbohydrate in sweets, fruits and milk are simple sugars (monosaccharides meaning one sugar, or disaccharides meaning two sugars). Starches are more complex arrangements of carbohydrates, which contain chains of sugars. These are found in grains, beans/legumes, potatoes, corn etc. Dietary fiber is the structural part of grains, beans/legumes, vegetables, and fruits that the body is unable to break down. Although our body does not break fiber down, once in the large intestine, resident bacteria ferment these fibers and break them down.
Insulin and the Glycemic Index
Once carbohydrate is digested, regardless of its source, it is converted to glucose in the blood. When your blood sugar rises this stimulates the pancreas to release the hormone insulin. Insulin then takes the sugar from your blood and transports it to your cells for energy. Carbohydrate is the brain’s preferred fuel source to function properly. Carbohydrate is also stored in the muscle and liver as glycogen. Without carbohydrates in your diet, you wouldn’t have the energy to keep active and exercise, or concentrate at work. If you eat too many carbohydrates just like if you eat too much protein or fat, it will be stored as fat on the body.
The glycemic index (GI) of foods is the rate at which a food causes your blood sugar to rise. It is ranked from 0-100. All foods are compared to glucose, which is given a value of 100. A high glycemic food (>70) is digested quickly, causing blood sugar to rise rapidly and insulin levels to surge. This leaves you feeling sluggish and tired, and often hungry sooner. High insulin levels may also contribute to cancer, heart disease, and diabetes. A low glycemic food (<55) is digested slowly, causing a slow rise in blood sugar and less insulin production. A smooth, steady rise in blood sugar leads to more consistent energy levels and improved appetite control.
It is important to realize a few key factors before using the glycemic index to plan meals. Firstly, not all high GI foods are unhealthy, nor should they be avoided. Carrots for example are rich sources of beta-carotene that are good for cancer and heart disease prevention despite having a high glycemic index. Consequently, not all low GI foods are healthy. For example ice cream is loaded with saturated fat and calories despite having a low glycemic index. It is also important to note that the glycemic index of a food changes when it is combined with another food. A good rule of thumb is to avoid eating high GI foods on their own as they can contribute to a low blood sugar reaction and hunger. When you combine a high GI food with a low GI food you get a medium GI value. When you combine a high GI food with a source of protein or fat again this will improve blood sugar control.
High Carb Diet Research
It is interesting to note that populations from around the world that have the lowest risk of disease eat a high-carb, low-fat diet. Eating whole grains protects against diabetes, while eating refined grains increases risk of diabetes. Eating whole grains decrease risk of heart disease and stroke and offers significant protection against colon and upper digestive tract cancer. There is a large difference between Mediterranean, Asian, and vegetarian high-carb, low-fat diets in comparison to North American high-carb, low-fat diets. Traditional Mediterranean, Asian, and vegetarian high-carb, low-fat diets contain plentiful whole grains, beans, fruits and veggies. This type of diet promotes weight loss, lowers triglycerides (blood fats), and protects against heart disease, cancer, and diabetes. On the other hand, North American high carb, low-fat diets rich in refined and processed foods such as low-fat cookies, baked chips, bagels and limited intakes of fruits and vegetables can promote weight gain, raise triglycerides, increase your desire for eating, and raise risk for heart disease, cancer, and diabetes.
There are many health benefits to consuming whole grains. Firstly they contain a good source of dietary fiber, which is helpful for digestive health, heart disease/diabetes prevention and treatment, and cholesterol reduction. Whole grains also contain antioxidants (vitamin E, tocotrienols, and flavanoids), which decrease formation of blood clots and may prevent the bad cholesterol from adhering to artery walls. Antioxidants also protect cells from damage therefore protecting against cancer. Whole grains are also important sources of zinc, selenium, copper, iron, and folic acid. Whole grains to eat more of include whole wheat bread, whole rye bread, brown rice, wild rice, flaxseed, barley, bulgar, millet, oat bran, oatmeal, quinoa, spelt, kasha (buckwheat), and kamut. Refined grains and carbohydrates to eat less often include white bread, white crackers, cookies/cakes/cereal bars, cornmeal, white pasta, white rice, and sweets.
Considering a Very Low-carb, High-protein Diet?
Here are some of the health risks and issues to consider before deciding to follow a very low-carb, high-protein diet containing a high level of animal proteins, few fruits, some vegetables, and few whole grains. This type of diet may increase the risk of heart disease and cancer because it is low in fibre, limited in antioxidants, contains fewer phytochemicals, and is high in saturated fat. Compounds called heterocyclic amines that are produced from cooking meat at high temperatures also increase the risk of cancer and it is likely that on a high-protein, low-carb diet you will be consuming a higher amount of meat. Although being deficient in protein is damaging to bone health, a high-protein diet also increases the risk of osteoporosis and bone fractures due to increased calcium losses. Another factor negatively influencing bone health is the potential for low calcium intakes on high protein plans since milk and yogurt contain lactose which is a carbohydrate. Decreasing the amount of grains in your diet will also lower the level of folic acid you consume. Folic acid is a B-vitamin that is involved in heart health and prevention of neural tube defects in a developing fetus. Consuming a high level of protein may also lead to kidney problems. Following a very low-carb, high-protein diet also has the potential for boredom or poor sustainability due to the fact it is restrictive and may not fit into typical family/social meals. There is also heavy reliance on animal/marine foods which has an environmental impact as well as a food safety impact from the pollutants, hormones, and antibiotic residues that may be contaminated in animal based foods. Finally, following a very low-carb, high-protein diet will not provide enough energy to support a healthy level of physical activity, and will have a detrimental effect on the performance of athletes.
The Whole Truth – 8 Tips on Protein and Carb Balance
Below you will find a summary of some of the key things to remember when examining protein and carbohydrate balance.
- A calorie deficit causes weight loss. Weight loss is independent of diet composition. Eating less carbohydrate, protein, or fat can cause weight loss.
- Research suggests the amount of weight loss following different plans is variable. This suggests that individualization of weight loss plans is likely needed.
- Our new Dietary Reference Intake (AMDR) (2002), suggests consuming 45-65% of your calories as carbohydrate, 10-35% of your calories as protein, and 20-35% of your calories as fat.
- Portion sizes of carbohydrate rich foods are important. Eating too much will contribute to an excess of calories. Many people that are inactive eat enough carbohydrate to fuel an ironman triathlete!
- Not all carbs are created equal. Examine the quality of the carbohydrates you are eating for improved blood sugar control and appetite control. Reduce the amount of sugars and sweets you eat as well as reduce refined carbohydrates you eat (white breads, white pastas, white rice etc.). Include more fruits, vegetables, beans/legumes, and whole grains.
- Ensure you have a source of protein at meals for fullness and improved blood sugar control.
- Eat every 3-4 hours for best energy and to help you avoid overeating.
- Be aware that reducing carbohydrate in your diet lowers the amount of water stored on the body. With every one gram of carbohydrate you eat, you store approximately three grams of fluid. Don’t be fooled – reducing carbs reduces weight quickly because of fluid shifts in the body.
- Also be aware that reducing the amount of carbohydrate in your diet does not necessarily reduce the amount of calories you are eating, therefore not impacting your weight. For example the Atkins? Friendly Chicken Bacon Ranch Wrap at Subway has 448 calories, 24 g total fat, 9 g saturated fat, 22 g carbohydrate, and 36 g protein. A 6 inch turkey breast sub from Subway with honey oat bread, and veggies contains 350 calories, 5.9 g total fat, 1 g saturated fat, 59 g carbohydrate, and 19.8 g protein. The Atkins? Friendly Wrap has more protein and less carbohydrate, but the calories are higher than the traditional 6 inch sub! You also get much more saturated fat which is a negative fat for your heart when consuming the Atkins? Friendly Wrap.
The Bottom Line:
- Are you getting caught up in the latest fad rather than following good quality nutritional research?
- Are you choosing something sustainable?
- Are you following a weight loss plan that also considers long term health?
- Change is a process not an event! Be patient, slow weight loss will be lasting weight loss.