An Overview of Dieting for Health: The Principles

Witnessing the rising trends in obesity and diseases of both the US and global populations, epidemiological studies have found a significant relationship between the changes in the diet of the populations and the deterioration in their health during the past 50 to 60 years. Consequently, changing the individual’s dietary style is the top priority for the public health agencies, organized medicine, and health and nutritional advocates. [1, 2, 3, 4] To help people choose the best dietary style, it is important to not quickly favor or disfavor one type of diets over the other. Rather, all diets deserve a careful review as to the advantages and disadvantages of each dietary style. Based on the review, individual can make an informed choice of diets for himself.
While there is an association between obesity and diseases such as diabetes mellitus, arteriosclerosis and atherosclerosis, coronary artery disease and many more, the relationship between them is not causative, but is concurrent. For example, obesity has been blamed for causing diabetes mellitus, insulin resistance, and metabolic syndrome. The diabetic patients, who also suffered from obesity and underwent bartiatric surgeries for weight loss, had improved their blood glucose level and increased their insulin sensitivity in a period of a few days to a few weeks immediately after surgery. Ironically, during this short postoperative period, the patients even had not had a significant weight loss yet. The improvement is simply a result of sending a majority of carbohydrate foods, which the patients ate after surgery, directly into the very last part of their small intestine for avoiding a thorough digestion and absorption. Thus, these patients were in fact on the carbohydrate-restricted diet by surgery. This observation contradicts the causative role of obesity in the development of diseases and affirms the ill impacts of carbohydrates on the health. [5, 6, 7]

This article, however, does not intend to lessen the significance of obesity in developing health problems. Rather, it emphasizes that dieting is for restoring and maintaining a good health, not solely for weight loss. Other than the bariatric surgery, weight loss can be accomplished in two ways, so long as the individual is willing to reduce his daily calorie intake less than the need for his daily activities. In other words, he can lose weight by either consciously starving himself or simply letting the satiety help him reduce the total calorie intake. [8, 9]
Although there are so many food items, recipes, menus, and cooking styles, excluding seasonings, vitamins, minerals, supplements and et cetera, all foods, are categorized into three macronutrients, namely carbohydrate, fat, and protein. In essence, carbohydrates are the source of sugars, including glucose, fructose, and galactose after absorption; fats are the source of triglycerides and cholesterol and are important for the cellular structures and functions, in addition to being stored in the adipose (fatty) tissue; and proteins are the source of amino acids and peptides, which are important for physiological functions and replenishing the tissue.

When glucose is in excess inside the body, with the help from insulin, produces glycogen (the storage form of glucose), triglycerides, and cholesterols. At the same time, insulin stops the breakdown of fats and proteins, or facilitates anabolism. Thus, excess in blood glucose helps gain weight. More importantly, in today’s food industry, fructose has been widely used as sweeteners from sucrose and high-fructose-corn syrup. Fructose increases the production of triglycerides and VLDLs (Very Low-Density Lipoprotein) in the liver, which has been a cause of non-alcoholic fatty liver. The latter has become a serious epidemic. [10]

When glucose is in short supply, the insulin level is normally low. Consequently, glucagon converts glycogen into glucose in glycogenolysis. Also, both fat and protein can be totally or partially converted into glucose for producing energy. The conversion is called gluconeogenesis, which helps lose weight. Understanding gluconeogenesis helps alleviate the unnecessary fear of carbohydrate-restricted diet. Although not all triglycerides can be converted into glucose, their metabolic intermediate, beta-hydroxybutyrate, which is a ketone but not the ketone in diabetic ketoacidosis. The brain, heart, muscles, and some other tissues can efficiently use beta-hydroxybutyrate as the source of energy. [11]

Keeping these general principles in mind, one can better understand the individual dietary style, which fits his need.

Robert Su, Pharm.B., M.D.

Wish to invite Dr. Su to speak at your meeting, contact us at jevpublishing@verizon.net

References:

1. Centers For Disease Control And Prevention. “Prevalence of overweight, obesity and extreme obesity among adults: United States, trends 1960-62 through 2005-2006.” NCHS Health E-Stat.

2. Centers For Disease Control And Prevention. “Obesity Prevalence Among Low-Income, Preschool-Aged Children — United States, 1998—2008.” Morbidity and Mortality Weekly Report. July 24, 2009 / Vol. 58 / No. 28

3. Ogden CL, et al. “Prevalence of High Body Mass Index in US Children and Adolescents, 2007-2008.” Journal of American Medical Association. 2010;303(3):242-249

4. JD Wright, MPH, J Kennedy- Stephenson, MS, CY Wang, PhD, MA McDowell, MPH, CL Johnson, MSPH, National Center for Health Statistics, CDC. “Trends in Intake of Energy and Macronutrients—United States, 1971-2000.” Journal of American Medical Association. 2004;291(10):1193-1194.

5. Gumbs AA, et al. “Changes in insulin resistance following bariatric surgery: role of caloric restriction and weight loss.” Obes Surg. 2005 Apr;15(4):462-73.

6. van Dielen FM, et al. “Insulin sensitivity during first months after restrictive bariatric surgery, inconsistency between HOMA-IR and steady-state plasma glucose levels.” Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery. 2009 Dec 11.

7. Kormer J. et al. “Bariatric Surgery in Diabetic Adults Improves Insulin Sensitivity Better than Diet.” The Endocrine Society. June 19, 2010.

8. Yancy, Jr., WS, et al. “A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia.” Annals of Internal Medicine.. Volume 140, Issue 10, Pages 769-777. May 18, 2004.

9. Ball SD, et al. “Prolongation of Satiety After Low Versus Moderately High Glycemic Index Meals In Obese Adolescents.” Journal of Pediatrics, Volume III, Number 3, Pages 488-494, in March 2003.

10. Su, R. “Non-alcoholic Fatty Liver Disease and Carbohydrate-rich Diet: An Epidemic Involves Both Adults and Children.” The Blog. Carbohydrates Can Kill June 30, 2010.

11. Su, R. “A Special Edition: “Do All Fats And Proteins Result In Glucose? NO!” The Blog. Carbohydrates Can Kill. July 27, 2010.