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Rapid Weight Loss: What is the right way to shed un-wanted pounds? And is rapid weight loss even possible?


Maya Benayoun

February 27th 2009






            “Drop 10 pounds in 10 days”, this slogan, along with numerous others, has led many Americans to believe that rapid weight loss is easy and healthy. Despite America’s obsession with fad diets and rapid weight loss alternatives, 66% of the American population is either obese or overweight (Dokken & Tsao, 2007). Consumers often fail to analyze labels on weight loss supplements and do not realize that melting off pounds in a short amount of time is not possible.  Taking a pill without the combination of diet and exercise will not lead to weight loss.  Misconceptions about types of dieting and weight loss alternatives that lead to the most efficient and long-lasting weight loss are prevalent within the American population. Some of the most common alternatives utilized by individuals seeking weight loss are high protein and/or low carbohydrate diets versus high carbohydrate and/or low fat diets, very low calorie diets (VLCD’S) versus low calorie diets (LCD’s), dietary supplements and gastric bypass surgery.


Basic Definitions: Obesity/ Overweight & Weight loss

            Obesity is a term that is often misused and misunderstood. An individual is considered obese if their Body Mass Index (BMI) is 30 or more and a person is considered overweight if their BMI is between 25 and 29.9 ( Being Obese and/or overweight results in increased health problems and susceptibility to weight related diseases. Weight loss is defined as any decrease in ones body fat, regardless of cause.  Individuals who are classified as either overweight or obese would be smart to make a decision to lose weight; the health benefits of such a choice are numerous, however many methods which are often resorted to are either unsafe or ineffective.


Low carbohydrate diets versus energy restricting diets; which works best?

            Low carbohydrate diets have become the most popular and widely used forms of dieting today. The Atkins diet and the South Beach diet are popular examples of a low carbohydrate diet. Low carbohydrate diets such as Atkins claim that although intake of ad-libitum products such as high-fat dairy products and meat products are apparent throughout the diet there is a restricted amount of fewer than 30 g of carbohydrates being eaten and, consequently, weight loss is significant (Astrup, Larsen, & Harper, 2004). These diets also claim that weight loss is fast, a healthy lifestyle is attained through the diet, and hunger is sustained. Although this diet sounds like the perfect solution to weight woes, studies have revealed that the reasons behind the weight loss are not exactly as advertised.

Various studies have been carried out to try and understand the long term results attained from a low carbohydrate diet in comparison to an energy restricting (energy=calories) diet. One study carried out in 2003 with 132 obese participants (39% of whom had type 2 diabetes and 43% who had metabolic syndrome) randomly placed participants on one of two diets. The first was a low carbohydrate diet and the second was an energy-restricting diet. These patients were reviewed six months after initiating the diets and the results were found to be as follows: the individuals placed on the low carbohydrate diets lost 3.9 kg more weight than those on energy restricting diets, however after 12 months the results were not found to be consistent with the earlier evaluations. Overall differences in weight loss were insignificant; in the long term, both categories of dieting result in about the same amount of comparable weight loss (Astrup, Larsen, & Harper, 2004). In a similar 12 month study which utilized 63 non-diabetic individuals, patients were either placed on the Atkins diet or on an energy restricting diet broken down into 25% fat intake, 15% protein intake and 60% carbohydrate intake. The results after 6 months had a high degree of correlation with the first study: the low carbohydrate study yielded better short-term results, 7% as opposed to 3.2% observed for patients on the energy restricting diet. However, after 12 months the differences in weight loss between the two diets became insignificant (4.4% versus 2.5%) (Astrup, Larsen, & Harper, 2004). 

The correlation between long-term weight loss and caloric or carbohydrate restriction was studied in two additional studies. One study preformed by Foster et al in 2003 tested 63 obese men and woman, all approximately 44 years of age. After 12 weeks of dieting those on the high protein diet lost an average of 6.7 kg of weight while those on the high carbohydrate diet only showed a 2.6 kg average weight loss. 24 weeks into the study those on the high protein diet (HP) lost 6.9 kg of body weight on average, while those on the high carbohydrate (HC) lost an average of 3.1kg. At the conclusion of the study 52 weeks after its initiation, the HP diet yielded an average 4.3 kg weight loss and the HC diet yielded an average 2.4 kg weight loss. The HP group consumed either 1500-1800 or 1200-1500 kcal/d (Buchholz & Schoeller, 2004).  Both of the studies showed the same large drop in weight within the first few weeks of dieting and a gradual decrease in that rapid loss afterwards. Why restrict carbohydrates when restricting calories will allow you to enjoy a variety of foods and maintain the same long-term, gradual weight loss? Most individuals would rather adhere to the Atkins diet than traditional dieting because results are observed at a significantly earlier time.  The main concern most nutritionists have posed with low carbohydrate diets relates to their effects on overall health. The American Heart Association released a diagram of what they believe to be a healthy diet.  The following chart demonstrates disturbing differences when compared to the Atkins diet breakdown.

 (Astrup, Larsen, & Harper, 2004)

            The amount of carbohydrates an individual consumes while adhering to the Atkins diet is 50% less than recommended and intake of saturated fat, non-saturated fat, as well as protein is increased dramatically. Short-term use of these low carbohydrate diets can yield beneficial results, but a long lasting healthy life style cannot be maintained if food consumption does not balance fat and caloric restriction. This may be a reason why low carbohydrate diets have been reported to result in “constipation, headaches, halitosis, muscle cramps, diarrhea, rashes and general weakness (Astrup, Larsen, & Harper, 2004)”.

Atkins has publically claimed that weight loss from his diet is attributed to increased energy expenditure, and a high protein diet does indeed increase daily expenditure by 2-3%, however this minimal amount cannot be viewed as a significant cause of weight loss. A significant portion of observed weight loss can be attributed to loss of water weight and loss of glycogen stores within the body as a result of carbohydrate restriction. It has also been shown that when high-protein foods are consumed, satiety is increased, and, consequently, food consumption decreases. (Astrup, Larsen, & Harper, 2004). When glycogen stores are used up because of low carbohydrate intake muscle loss and dehydration result in a large drop in body weight ( This weight reduction is not actual loss of body fat, and conclusively results from low carbohydrate diets can be deceiving, and this type of diet is not necessarily a healthy way to diet.


Very low calorie diets versus Low calorie diets

            Very Low Calorie Diets (or VLCD’s) are not a common way to lose weight and are usually only recommended in extreme cases of obesity. VLCD’s are often performed under medical supervision to guarantee efficiency. Follow up treatments reinforce the diet and assure that health conditions improve over time. These diets are extremely difficult to adhere to because they require a 50% or greater cut in caloric intake per day. Very low calorie diets are defined as diets that consist of 400-800 kcal/d diet while their counterpart, the low calorie diet, consists of 800 to 1200 kcal/d (Saris, 2001). The differences in the immediate and long-term ( 16 to 26 weeks) weight loss observed between low calorie diets and very low calorie diets are nearly the same as those observed when examining the differences between results from low carbohydrate diets and energy restricting diets. As with most diets that restrict a large portion of energy intake, weight loss is rapid and noticeable during the first 2 weeks of dieting. This weight loss can be accounted for by the loss of fluid (as energy is restricted ketone levels increase and water loss occurs) and loss of glycogen. In a 24-week study done by Foster et al. in 1992, women were placed on either a VLCD or a LCD. The 21 women restricting their energy intake to 420-kcal/d lost 0.8 kg/week and viewed a 19.5 kg change in their overall weight. The 23 women placed on a 660-kcal/d diet lost 0.9 kg/week of body weight and demonstrated an overall change of 22.6 kg in body weight. The 24 participants placed on an 800-kcal/d diet also displayed a 0.8 kg/week weight loss and a change in body weight equal to 90.6 kg.  A different study conducted in 1997 by Rossner and Flaten showed that kg/week loss is nearly identical with LC diets and VLC diets. In their study the first group of 20 women and 10 men were restricted to 420 kcal/day and lost 0.7 kg/week. The second group consisting of 22 women and 10 men was restricted to 530 kcal/day and lost 0.8 kg/week. The final group on the low calorie diet was restricted to 880 kcal/day and lost 0.7 kcal/d (Saris, 2001). The results of these experiments further support the idea that it is pointless to retain a very low calorie diet (which is extremely hard to maintain) when a low calorie diet will allow one to lose the same amount of weight. The reported side effects faced by individuals placed on a VLCD are more extreme then those placed on LC diets. If observed weight loss is equal and side effects are less severe, an individual should consider a LC diet over a VLCD.

The long-term effectiveness of both very low calorie diets and low calorie diets has been researched, however no definitive conclusions have been made. Some researches believe that very low calorie diets result in the re-gain of weight that is equal to or more than original body weight while other researchers have stated the opposing opinions. One study conducted by Sikand et al in 1988 followed up on 10 women who were originally placed on a very low calorie diet and found that 2 years after their diet had ended they faced a 95% regain of initial weight loss (Saris, 2001). In a similar study done by Wadden et al. in 1989 of 22 women originally on a 1200 kcal/day low calorie diet faced a 49% regain in initial weight loss after one year and an 121% regain after 5 years (Saris, 2001).

            Although it has not yet been determined which form of dieting keeps weight off for a longer period of time the short term similarities should be enough to cause an individual to re-consider partaking in a very low calorie diet. Diets such as these should not be undertaken for long periods of time because losses in protein have proven to be extremely harmful to the body. These diets should only be resorted to in extreme cases in which significant weight loss must occur rapidly to reduce health problems associated with obesity.


Short and long term side effects of VLCD’s and LCD’s

            Individuals that have taken part in a very low calorie diet have reported side effects such as “dry mouth, constipation, headache, dizziness/prthostatic hypotension, fatigue, cold intolerance, dry skin, menstrual irregularities, and hair loss (Saris, 2001).” In addition, a very low calorie diet, along with other forms of rapid weight loss, puts participants at risk for gallstone formation ( Individuals on low calorie diets, can also experience these observed side effects, but to a smaller extent. Despite these side effects, there are many benefits of a very low calorie diet for those who had health risks as a result of their weight beforehand. These benefits include a decrease in the extremity of diabetes mellitus and an improvement in blood pressure rates (Saris, 2001).


Gastric Bypass and Dietary Supplements

            Gastric Bypass surgery is a procedure in which the top of the stomach is stapled and a small pouch is formed. The decreased size of the stomach reduces hunger and the amount of calories consumed, and the pouch allows some food to bypass the small intestine. When food bypasses the small intestine fewer nutrients are absorbed and less fat is produced. The surgery should not be taken lightly, as it leads to an extremely restricting and somewhat uncomfortable lifestyle. Most individuals should not turn to this form of weight loss unless it is an absolute necessity and individual health is at risk (BMI is usually above 40). Gastric bypass surgery results in “ dumping syndrome” which  means that trips to the bathroom are a frequent occurrence, and nausea, weakness and sweating are other side-effects of the procedure (

(                       (, Star Jones underwent a gastric bypass surgery. The results were significant and the surgery proved effective in rapid weight loss.

            Another frequent way to lose weight rapidly is through the use of dietary supplements. Many people who want to lose weight quickly believe it is easy to do so by taking a weight loss pill without changing their diet or exercise routines. These supplements have only proven effective when combined with dieting and exercise. Commercials for supplements attribute weight loss to a wide range of causes. Some pills such as the FDA approved supplement Alli; block fat from being absorbed after meals. The unabsorbed fat is then released during bowel activity ( . Other supplements, such as Phentermine (a prescription supplement), are hunger suppressants that trick your body into believing it is full when it is not (by increasing serotonin levels) and thus, causing a reduction in food consumption. Most dietary supplements have been shown to lead to a minimal amount of weight loss and take a long period of time to work. The side effects of such supplements include “increased heart rate, increased blood pressure, sweating, constipation, insomnia, excessive thirst, lightheadedness, drowsiness, stuffy nose, headache, anxiety and dry mouth” ( The various supplements, which do not result in significant amounts of weight loss, have side-effects and risks that outweigh their benefits. 



            Not everyone has the so-called ideal body and many Americans would like to lose a few pounds as quickly as possible, but rapid weight loss is not sustainable. Deciding to lose weight is healthy for individuals not within an ideal BMI, however weight loss should be taken seriously and the benefits and risks of methods should be evaluated thoroughly prior to beginning a particular regimen. If all an individual’s goal is to lose 10 to 20 pounds I would recommend an energy restricting diet combined with regular exercise because it will lead to weight loss and a lasting healthy lifestyle. Going on the Atkins low carbohydrate diet will lead to weight loss as well, but it is harder to uphold and has been shown to lead to long term results that are nearly identical to those of a low calorie diet. If current weight has lead to health complications I would recommend a low calorie diet because immediate weight loss is necessary to avoid any serious health problems in the immediate future. A very low calorie diet would be equally effective, but will be significantly harder to maintain, and should not be undertaken without medical supervision and behavioral therapy. In addition, I would not recommend a gastric bypass surgery unless all other alternatives have been exhausted. If weight-related health problems are serious and weight his out of control, gastric bypass surgery is effective and will help improve health conditions. Unless their weight situation is extreme, someone should not opt to undergo gastric bypass surgery probably because its effects on the body and on a person’s lifestyle are substantial, and a complete change in eating habits is necessary. Lastly, I do not believe in the effectiveness or health benefits of dietary supplement usage. There is not sufficient research on the long-term effects of dietary supplements available, and weight loss has been shown to be minimal.  Due to these findings I have found that conventional dieting and exercising is a better alternative. Pill usage may lead to heart complications and other health issues, and the risks are not worth the results gained. What is important is not the amount of weight which is to be lost, but the manner in which weight loss is achieved.


            (1) Astrup, A., Larsen, T. M., & Harper, A. (2004, September). Atkins and other low-carbohydrate diets: hoax or an effective tool for weight loss? Rapid Review , 897-899.


(2)Buchholz, A. C., & Schoeller, D. A. (2004). Is a calorie a calorie? The American Journal of Clinical Nutrition , 899-903.


(3)Dokken, B. B., & Tsao, T.-S. (2007). The Physiology of Body Weight Regulation: Are We Too Efficient for Our Own Good? Diabetes Spectrum , 166-169.


(4)Saris, W. H. (2001, November). Very-Low-Calorie Diets and Sustained Weight Loss. Obesity Research , 295-301.







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