In recent years, carbohydrates have been labeled as the nutrition ‘bad guy’ because of the increases in insulin that occurs during metabolic processes. The secretion of insulin is dependent primarily upon the concentration of blood glucose – an increase of blood sugar brings about an increase in the secretion of insulin. Therefore, one function of insulin is to lower glucose.
Conversely, the body increases blood glucose levels by secreting another hormone called glucagon.
If blood glucose levels remain high, and that energy source is not burned shortly after it is consumed, the excess glucose is shuttled off to the muscles for storage. If the muscles have reached their limit in storage capacity, and the body does not require extra glucose to sustain body activities, the excess converts to fat.
Also, as insulin efficiently clears the blood of excess sugar, blood sugar levels oftentimes dip below normal and will produce the infamous ‘sugar blues’ or a ‘downer’, followed by a possible craving for more sugar consumption. Lastly, while insulin levels are high or active, the body will not burn fat as energy since the body is attempting to utilize as much blood sugar as possible. (Note that fat is not used as a primary energy source while eating an energy-sufficient, healthy diet and fat is used more heavily only during periods of fasting and extensive aerobic-type exercise.) Hence, ‘high-fat-low-carb’ advocates claim that we should not want:
1) Excess carbs to turn into fat (what do they think happens to excess fat and protein kcal?);
2) To feel groggy with low energy from the insulin ups and downs associated with high carbohydrate (sugar) consumption; and
3) High carbs in the diet since they prevent us from burning body fat.
Although these factors are true, the extent or magnitude of their validity varies in accordance to a number of conditions, such as:
i) How active is the individual?
ii) How many kcal is the individual ingesting (including carbs) per meal?
iii) What comprises an individual’s food and carbohydrate intake?
HOW ACTIVE ARE YOU?
The more active a person, the more carbohydrate he or she should consume. Also, the greater the physical activity, the less insulin the body produces since muscles become insulin sensitive after exercise and glucose tolerance improves as a result. The Food Guide/Pyramid recommends about 50% of kcal in the average individual’s diet to be in the form of carbohydrate. Therefore, if a person is very active, the amount should be increased to about 60% since nearly every activity uses a great deal of blood glucose and muscle glycogen for energy, but only a smaller percentage of fat. In fact, athletes who consume a high-carb diet (60%) can maintain higher-intensity exercise longer than those following a low-carb diet (www.ExerciseCertification.com)
Brian D. Johnston is the Director of Education and President of the I.A.R.T. fitness certification and education institute. He has written over 12 books and is a contributor author to the Merck Medical Manual. An international lecturer, Mr. Johnston wears many hats in the fitness and health industries, and can be reached at info@ExerciseCertification.com.
Visit his site at http://www.ExerciseCertification.com for more free articles.
