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Fat and Fiction

Meghan Habig




What is the intention of a low carbohydrate, high protein diet?


          The main purpose of a low carbohydrate, high protein diet is to lose weight quickly by eating many high in protein foods. Foods like steak, chicken, nuts, and eggs all have high protein and little to no carbohydrates.  Many people use this diet as a quick weight loss.  However, this as it explains below, is not the healthiest way to lose weight.  Most people are looking for an easy solution to lose weight rapidly without putting in the effort that a low-calorie diet requires.  As obesity has been on a rise, people have been looking to fad diets for answers.  Eating an overabundance of anything is harmful to the body.  This diet was popular in the 1970s when refined sugar was supposed to be bad.  After several reports of heart disease, this fad slowly faded.  Now that the emphasis in our society is back on weight issues, this easy way to lose weight has gained back all of its popularity and more. 




What are carbohydrates and protein? 


The intake of carbohydrates, which are rich in sugars or starches, sparks the release of insulin.  This insulin slows down the fat-burning mechanisms.  This means that insulin slows down the body’s capability to burn fat.  On the other hand, proteins are complex organic compounds.  The structure consists of a chain of amino acids, in which contain carbon, hydrogen, oxygen, and nitrogen.  The nitrogen is what makes protein different from both fat and carbohydrates.  Carbohydrates function as the primary energy source for the body, brain, and nervous system.  Glucose, which is sugars and starches that have been broken down, is the energy used for the body.    It is recommended that a person should receive anywhere between 40-60% of total calories from carbohydrates.



Is this diet healthy?


High protein diets encourage the over-consumption of cholesterol and saturated fat.  These increase the chances of heart disease.  The body burns fatty acids when there is not an adequate amount of carbohydrates.  Due to this, the kidneys could be overworked resulting in damage during the process.  Some side effects include nausea, dehydration, dizziness, constipation, tiredness, headaches, and bad breath due to ketones, chemicals released in the bloodstream. At, they state that “any high protein diet which bans carbohydrates is a danger to your health and should be avoided. Even more moderate high protein diets should not be followed by anyone with a history of ill-health, especially anyone with weak kidneys.”  Also, extra waste is excreted in the urine.

          Moreover, by lacking fruits, cereal, vegetables, and a variety of other healthy foods, the body may be deprived of certain necessary vitamins, antioxidants, and minerals that help to fight cancer and maintain strong bones.  According to researcher Neal Barnard, M.D., the high protein diet is very harmful and works in a way that harms the body instead of helping it.  This kind of diet “throws the body into a state of ketosis, a metabolic derangement that temporarily burns fat.  But it misses the fiber and antioxidants that protect against cancer and other serious diseases” (  Clearly, it is neither smart nor healthy to deprive a body of carbohydrates.


What are some claims made about the effectiveness of this diet?


As this diet becomes increasingly popular, the claims seem to get more exaggerated.  One claim, said that the triglycerides, cholesterol, and body fat would decrease down to a very healthy level (  Many claim that this diet is one that is very easy to follow because it reduces the cravings and the hunger pangs that usually make people gain weight.  All this is done by simply restricting simple carbohydrates.  This same site claims that men will typically lose 6-8 pounds in the first two weeks while women lose 4-6 pounds.  After the first two weeks, dieters average 1-2 pounds per week. 

At, the founder and webmaster states that:  “EATING FAT does not make us fat!”  On such diets as Diet Divas, (, people have said that this high protein diet is simple, but with enough variety to keep them interested.  “The carbs were the enemy.”  “I’ve enjoyed the diet and have not been hungry once.”  “I have tried every diet in the world.  The protein snacks are delicious and in fact I look forward to them everyday.”



Weight Loss Testimonials

Weight Lost (Ibs)

Amount of Time


8 weeks


15 weeks


2 weeks



“Diets that have you feast on meat, eggs and other proteins while skimping on fruits, vegetables and cereals are not only risky if you stay on them for long, but, to add insult to injury, they won't even keep the pounds off, says the American Heart Association (AHA) (”  This statement is relating to all of the risky side effects that come from high protein diet.



What evidence if any is offered in support of the claim?


There is little to no evidence supporting the claims above.  The testimonials found on the Diet Diva page had the first names of each person making the statement, but no evidence to back it up.  Beside the fact that weight was lost, there was no medical evidence on how it was actually lost and what the side effects were.  It seems like it was almost left out of the website.



 Dr. Barnard’s statement at, had much medical evidence to support him.  More evidence is used to back up the fact that the high-protein diet is not a healthy choice.  The evidence was supported with scientific logic.  Another well backed statement is the one from the American Heart Association, which is very reliable and well researched.  The American Health Association confirmed that the weight loss was due to the deficit of water which happens after the lack of carbohydrates. 





Who is presenting this information, and why are they presenting it?


          Most of the pro-protein diet information comes from people trying to sell products.  Some products that are sold can be found at  Apparently, the sellers want to vend their products and in order to do this, they must first sell their information.  Most of these sites have a disclaimer at the bottom stating that the Food and Drug Administration has not evaluated the website. 


          The claims that low-carbohydrate diets are unhealthy come from doctors, physicians, and people trying to help inform the world.  Each website was not trying to sell anything and stated that the information should not substitute for professional medical advice.






Other Good Places for Information




The Adkins Center




·        Entering the Zone by Dr. Sears

·        Dr. Atkins low-carbohydrate Diet

·        Protein Power by Dr. Michael Eades and Dr. Mary Eades




How do low carbohydrate diets initially produce greater weight loss?


Low carbohydrate diets reduce the daily caloric intake by 500 kcal/day.  This should result in 0.45-0.91 kg of weight loss each week.  By ridding the daily food intake of some of the most popular foods, such as pizza, bread, French fries, and soft drinks, the calories consumed each day significantly decrease.  This produces an initial weight loss of 2 to 3 kg weight loss in the first week alone. 


          Such a significant weight loss in the first week occurs from two different processes.  The first process is mobilization of glycogen.  Glycogen is stored in the liver and muscle.  The liver can store up to 100g of glycogen; whereas, muscle can store as much as 400g of glycogen.  Each gram of glycogen is mobilized by 2g of water.  This accounts for the “bloating” that people on the low carbohydrate diet usually do not experience.   This results in a weight loss of 1 kg.  The second process is the generation of ketone bodies.  Ketosis is a condition in which the incomplete breakdown of fatty acids comes from the decline of glucose in the bloodstream which then causes the production of ketones.

          Most of the people on the low carbohydrate diet say that they experience less of an appetite.  This results from two different reasons.  From eating high protein, one may feel that their appetite is suppressed.  The second reason comes from ketosis due to the carbohydrate restriction.




What are some of the Metabolic Effects?


        There are several metabolic effects resulting from a high protein, low carbohydrate diet.  The first was mentioned above:  ketosis.  Ketosis has been found to alter cognitive functions.  A study was done involving a ketogenic diet with a nonketogenic diet.  The ketogenic diet proved to have impairments in higher order mental processing and flexibility than those that followed a nonketogenic diet.  (7)


          The second metabolic effect would be from the high saturated fat intake.  It has been found that by consuming high saturated fat, cholesterol levels have also risen.  Cholesterol is thought to promote scarring of the arteries.  A study with twenty four subjects that underwent an eight-week Atkins’ type diet, showed an increase in low density lipoprotein cholesterol level.  This increased from 127 to 151mg/dl.  The total cholesterol also increased by 13%.  (4)




          The last metabolic effect that a low carbohydrate diet has is from the exclusion of fruit, vegetables, and grain.  A diet void of deficient of fruit, vegetables, and grain is one that also deprives a person of micronutrients.  Even a low carbohydrate diet that has supplemental multivitamins, this does not replace the biologically active phytochemicals found in fruits, vegetables, and grains.






Besides all these metabolic effects, does the diet still work?


          Besides ketosis, high cholesterol, and not enough micronutrients, the low carbohydrate diet does work.  Since the diet has become so popular in the last decade, many studies have been done to see if it does exactly work.  One such study was performed with 41 obese people that were otherwise healthy.  They were restricted to less than 25 grams of carbohydrates a day.  No limits were set on their caloric intake.  The study was based on body weight, body mass percentage, percent of body fat, serum chemistry and lipid values, 24-hour urine measurements, and subjective adverse effects. 


          After six months, results showed that sustained weigh loss occurred.  There were no adverse effects found.  Body weight had decreased by 10.3% while percentage of body fat had also decreased by 2.9%.  The body mass index decreased by 3.2kg/m2.  The serum bicarbonate decreased 2mg/dL.  The low-density lipoprotein decreased by 10mg/dL and the high-density lipoprotein increased by 10mg/dL.  This study was just one of many that have been conducted showing that the diet does indeed work to reduce weight. (6)


        Another study was performed with 24 obese men and women.  During the first two weeks, the subjects were allowed to consume their normal food intake.  The next eight weeks consisted of a high protein, low carbohydrate diet.  The last two weeks consisted of the normal food intake.  This study found, once again, that a low carbohydrate diet helps weight loss substantially.  (2)


What other studies have been done?


          Some people have claimed that the low carbohydrate diet leaves them weak and unable to exercise.  A study was done to see if the restriction of carbohydrates does impair aerobic exercise capacity.  This was found to be false.  A short-term ketogenic diet does not impair exercise.  Even the Greek Olympians ate high meat, low vegetable diets over 2000 years ago to improve athletic performance.  (3)

          A study was also done on high-animal protein, low-carbohydrate diet during pregnancy.   A follow-up study of 626 men and women was conducted.  The mothers of these people had recorded food intake during pregnancy.  The 626 people had their systolic and diastolic blood pressure recorded.  The study found that higher blood pressure results from a high-protein, low-carbohydrate diet during the mothers’ pregnancy.  This is guessed to be from the metabolic stress endured from an unbalanced diet. (5)







1.  Atkins R.C. Dr. Atkins’ New Diet Revolution, Simon & Schuster, New York (1998).




2.  Langfort J, Pilis W, Zarzeczny R.

Effect of low-carbohydrate-ketogenic diet on metabolic and hormonal responses to graded exercise in men.

Journal of Physiology and Pharmacology. 47 (1996), pp. 30-36



3.  Larosa J, Fry A, Muesing R, Rosing D.

Effects of high-protein, low-carbohydrate dieting on plasma lipoproteins and body weight.

Journal of Dietetic Association. 77 (1980), pp. 264-270



4.  Rickman F and Mitchell N,

Changes in serum cholesterol during the Stillman diet. JAMA 228 (1974), pp. 54¯58.



5.   Shiell AW, Campbell-Brown M, Haselden S, Robinson S, Godfrey KM, Barker DJ.

High-meat, low-carbohydrate diet in pregnancy: relation to adult blood pressure in the offspring.
Hypertension. 2001 Dec 1;38(6):1282-8.
PMID: 11751704 [PubMed - indexed for MEDLINE]



6.  Westman EC, Yancy WS, Edman JS, Tomlin KF, Perkins CE.

Effect of 6-month adherence to a very low carbohydrate diet program.
Am J Med. 2002 Jul;113(1):30-6.
PMID: 12106620 [PubMed - indexed for MEDLINE]




7.  Wing RR, Vazquez J, and Ryan C,

Cognitive effects of ketogenic weight reducing diets. Int J Obes Relat Metab Disord 19 (1995), pp. 811¯816.




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