Low-Carb Dieting

What does the research say?

By Rowan Goodrich
Clinical Nutrition Manager, Providence Hospitals

Americans are struggling with the overweight and obesity epidemic and the repercussions are seen in many facets of our lives, including our escalating health care costs.  As our nation’s waist lines expand, an increasing number of dieting strategies are evolving, many of them are short lived like the “Grapefruit Diet” or the ”Hollywood Diet” .

Low-carbohydrate dieting, however, continues to be a popular method for shedding those extra pounds.  If you have ever talked to someone about their weight loss story with the low-carb method, undoubtedly they will tell you that it works and it works fast!  The research confirms these statements.  Glycogen stores are depleted whenever an individual has a reduced carbohydrate intake and the result is dramatic weight loss.  The primary energy source for our brain is carbohydrate.  As the low-carbohydrate diet continues, ketones are produced to fuel the brain with energy.  It is suggested that these ketones may help with diet adherence because of decreased hunger.  It is also generally accepted that proteins, rather than carbohydrate, suppress food intake and increase the feeling of fullness.  Research indicates that an increased protein diet also delays the return of hunger.

What does the long-term research say about low-carb diet and weight loss?  There is not enough information in studies to say that this diet is harmful for everyone.    The long-term effect on weight loss maintenance is very telling.   Although people on a low-Carb diet did loose more weight initially after 6 months than those on a low-fat, reduced calorie diet, the difference after a 12 month period was not significant.   Unfortunately, the weight comes back on with a vengeance as soon as the diet plan is discontinued.  Many people will ride the weight loss roller coaster and cycle off and on these diets causing large weight fluctuations in a short amount of time.

Any diet that involves strict omission of a food or food group should raise a red flag.  Compliance will be a struggle when there is too much emphases on restriction and it is very often the dieter will fail in the long-term.  Although the low-carb diet guidelines may be “easy” in the initially, the craving for omitted foods grows and develops into a gnawing hunger.  It could be a disaster as the dieter comes into contact with a mashed potato bar and they cave into the starchy craving.  Next comes the feeling of failure and more eating to help numb the pain.  The above scenario may sound dramatic, but simply put, diets fail because people will try to follow a dietary habit that is so different from a “normal” balanced eating pattern and it becomes a struggle to keep it up.  Restriction diets cause individuals to have an unhealthy relationship with food.  You can become obsessed with everything that goes on your plate and feel envious of those eating a slice of chocolate cake.

My advice to you is to be smart about your dietary choices and exercise.  Do not omit a food and do not overindulge in a food.  If you want chocolate cake, have a small slice so you don’t feel restricted (Just don’t have a small slice three times a day!).  The National Weight Control Registry is a registry of more than 3,000 individuals who have successfully maintained at least a 30 lb weight loss for a minimum of 1 year.  More than 90% report exercise as crucial to their long-term weight-loss maintenance.  They report expending, on average, 2,682 kcal per week in exercise, an energy equivalent to walking 4 miles 7 days a week.

Successful weight management takes a lifetime commitment to healthful lifestyle behaviors including sustainable and enjoyable eating practices.  Successful weight loss maintenance is determined by multiple variables such as metabolism, presence of depression, perception of weight loss success, self-monitoring, level of physical activity, and stressful life events.    I wish you well in your weight loss/management endeavors.

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Pleuss, J., & Phillips, S.  (2006).  The effect of a low fat diet compared to a low   
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Seagle, H., & Strain, G.  (2009).  Position of the American Dietetic Association: Weight  
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