Low-carb diet causes nearly twice as much weight loss as low-fat: 26 lbs vs 14 lbs

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Patients eating a low-carbohydrate group lost nearly twice as much weight as those in the low-fat group. Those in the low-carb group lost an average of 26.4 pounds versus 14.3 pounds for those in the low-fat group. Weight Loss

Weight Loss: 12.9% VS 6.7%

As a percent of starting weight this represented 12.9 percent for the low-carbohydrate group and 6.7 percent for the low-fat group.

It is important to point out that the calorie intake of the low-carbohydrate group was not restricted, whereas the calorie intake of the low-fat group was. As is noted below, both groups ate roughly 1500 calories per day, however, the low-carbohydrate group lost nearly twice as much weight.

One possible explanation for this is that a high-protein increases metabolism according to the authors. (p. 775, col. 2)

 

Weight Loss Compared to Diet Pills Xenical and Meridia

Low-Carb Weight Loss Greater Than With Xenical Or Meridia: 13% Vs 9% Vs 8%

The average weight loss in low-carbohydrate group was greater than the average weight loss seen with Xenical (orlistat) which causes an average weight loss of about 9 percent after six months according to the authors of the study, and greater than the average weight loss seen with Meridia (sibutramine) which causes an average weight loss of about 8 percent after six months according to the authors of the study. (p. 775, col. 1)

 

10% Weight Loss or More

How Many Lost At Least 10 Percent: 61% Vs 23%

Nearly three times as many patients in the low-carbohydrate group lost at least 10 percent of their body weight as those in the low-fat group: 61 percent of of the group versus 23 percent.

 

Fat Loss

Fat Loss: 20.7 Lbs Vs 10.6 Lbs

Patients in the low-carbohydrate group lost nearly twice as much body fat as those in the low-fat group: 20.7 pounds versus 10.6 pounds.

Average percent body fat decreased from 41 percent to 35 percent in the low-carbohydrate group compared to from 41 percent to 38 percent in the low-fat group.

 

Muscle Loss

Muscle Loss: 20.7 Lbs Vs 10.6 Lbs

Patients in the low-carbohydrate group lost slightly more lean body mass than those in the low-fat group: 7.3 pounds versus 5.3 pounds. This is the result of losing more body weight.

 

Triglycerides

Triglycerides: -74 Mg Per Deciliter Vs -28 Mg Per Deciliter

There was a greater decrease in triglycerides levels in the low-carbohydrate group than those in the low-fat group: -74 mg per deciliter vs -28 mg per deciliter.

 

HDL

HDL: +6 Mg Per Deciliter Vs -2 Mg Per Deciliter

There was an increase in HDL cholesterol levels in the low-carbohydrate group ??? which is associated with a decrease in the risk of heart disease ??? whereas there was a slight decrease in the low-fat group: +6 mg per deciliter vs -2 mg per deciliter.

HDL went from 55 to 61 mg/dL in the low-carb group, and 54 to 52 mg/dL in the low-fat group.

It should be noted that HDL levels usually drop when a person is losing weight and then increases when a person???s weight stabilizes. The increase in HDL levels seen in low-carb group is known to occur when carbohydrates are replaced by saturated, monounsaturated, or polyunsaturated fat according to the authors. (p. 775, col. 2)

 

LDL

LDL: +2 Mg Per Deciliter Vs -7 Mg Per Deciliter

Levels of LDL cholesterol increased by 2 mg/dL in the low-carbohydrate group ??? which is associated with a increase in the risk of heart disease ??? whereas there was a decrease in the low-fat group of 7 mg per deciliter.

LDL levels increased by more than 10 percent in one-third (30 percent) of people in the low-carb group. (p. 775, col. 2)

The authors note that in an uncontrolled trial of twenty-four people on the low-carb diet, LDL levels increased by 24 mg/dL after two months.

Hoever, another low-carb study that involved forty-one pople found that LDL levels decreased by 10 mg/dL after six months.

Blood lipids should be monitored for anyone on a low-carb diet since it may increase LDL according to the authors of the study. (p. 775, col. 2)

 

Systolic Blood Pressure

Systolic Blood Pressure: -10 mmHg VS -8 mmHg

Systolic blood pressure decreased by 10 mmHg low-carbohydrate group compared to 8 mmHg in the low-fat group.

 

Diastolic Blood Pressure

Diastolic Blood Pressure: -6 mmHg VS -5 mmHg

Diastolic blood pressure decreased by 6 mmHg low-carbohydrate group compared to 5 mmHg in the low-fat group.

 

Pulse Rate

Pulse Rate: -9 Beats Per Minute Vs -10 Beats Per Minute

Pulse rate decreased by 9 beats per minute in the low-carbohydrate group compared to 10 beats per minute in the low-fat group.

 

Insulin Sensitivity

Insulin Sensitivity: Previous Studies Show Low-Carb Increases Sensitivity

Insulin sensitivity was not measured in this study, but previous studies have found that low-carb diets lower blood sugar and insulin levels according to the authors. (p. 776, col. 1)

 

Low-Carb in Metabolic Syndrome

Low-Carb Diet May Be Warranted In People With Metabolic Syndrome

The positive changes in body weight, blood pressure, and serum lipids suggest that a low-carb diet may be beneficial for people with metabolic syndrome, also known as Syndrome X, which is characterized by excess belly fat, insulin resistance, increased blood pressure, elevated triglycerides, and low HDL levels.

 

Adverse Effects

Adverse Effects

Adverse effects were more common in the low-carb group than the low-fat group.

Constipation occurred in 68 percent of patient in the low-carb group versus 35 percent of patients in the low-fat group. One patient in the low-carb group sought medical attention for constipation.

Headaches occurred in 60 percent of patient in the low-carb group versus 40 percent of patients in the low-fat group.

Bad breath occurred in 38 percent of patient in the low-carb group versus 8 percent of patients in the low-fat group.

Muscle cramps occurred in 35 percent of patient in the low-carb group versus 7 percent of patients in the low-fat group.

Diarrhea occurred in 23 percent of patient in the low-carb group versus 7 percent of patients in the low-fat group.

General weakness occurred in 25 percent of patient in the low-carb group versus 8 percent of patients in the low-fat group.

Rash occurred in 13 percent of patient in the low-carb group versus 0 percent of patients in the low-fat group.

Adverse Effects: Low-Carb Diet May Increase The Risk

A recent study found that a 2,000 calorie low-carb diet may increase the risk of kidney stones according to the authors of the study. (p. 776, col. 2)

They noted that the nutritional supplements included citric acid, which may have helped prevent formation of kidney stones according to the authors. (p. 776, col. 2)

 

Serious Adverse Effects

Serious Adverse Effects

A 53-year-old man in the low-carbohydrate group developed chest pain near the end of the study, and was subsequently diagnosed with coronary heart disease. He had a family history of early heart disease. During the study he had lost 35.2 pounds, his LDL cholesterol had dropped by 29 mg/dL and his HDL cholesterol had increased by 8 mg/dL.

 

Dropouts

Droupouts: 3 In The Low-Carb Group

Three people the low-carbohydrate group dropped out of the study because of adverse effects. Two had increases in LDL cholesterol, and one experienced shakiness and uneasiness.

 

Finishing the Study

More In The Low-Carb Group Finished The Study: 76% Vs 57%

More people in the low-carbohydrate group than in the low-fat group completed the six month study: 76 percent versus 57 percent.

 

Low-Carb Diet

The Low-Carb Diet: Less Than 20 Grams Per Day

The low-carbohydrate diet consisted of limiting carbohydrate intake to less than 20 grams per day, took nutritional supplements, were recommended to exercise and had group meetings.

The nutritional supplements included fish oil, which has been shown to decrease triglycerides and slightly increase levels of LDL and HDL according to the authors. (p. 776, col. 1)

An analysis of what they ate found that they actually consumed an average of 30 grams of carbohydrates per day or 8 percent of calories, 98 grams of protein or 26 pecent of calories, and 111 grams of fat or 68 percent of daily calories.

 

Low-Fat Diet

The Low-Fat Diet: Less Than 30% Of Calories From Fat

The low-fat diet was designed to be 500 to 1,000 calories per day less than a person???s needs, less than 30 percent of calories from fat, less than 300 mg of cholesterol per day, plus a recommendation to exercise and group meetings.

They also took nutritional supplements, were recommended to exercise and had group meetings.

An analysis of what they ate found that the low-fat group consumed an average of 198 grams of carbohydrates per day or 52 percent of calories, 71 grams of protein or 19 pecent of calories, and 49 grams of fat or 29 percent of daily calories.

 

Calorie Intake

Calorie Intake: 1500 Calories In Both Groups

An analysis of self-reported intakes estimated calorie intake to be an average of 1461 calories per day in the low-carbohydrate group, and 1502 calories in the low-fat group.

It is important to remember that the calorie intake of the low-carbohydrate group was not restricted. In other words, this type of diet spontaneously caused a reduction in calorie intake without any specific instructions to do so.

 

Subjects

Subjects

One-hundred twenty people started the study. They were 18- to 65-years-old with a body mass index of 30 to 60 (obese to extremely obese) with a total cholesterol level of 200 mg/dL or more, LDL levels of 130 mg/dL or more, or triglycerides of 200 mg/dL or more, and no serious medical conditions.

 

Criteria: No Diet Pills Recently

No Diet Pills In The Previous Six Months, Other Medications In The Previous Two Months

Patients were excluded if they had taken any prescription weight loss medicine in the previous six months or any other prescription medication in the previous two months except for birth control pills, estrogen therapy or stable thyroid medication.

 

Study Support

Study Supported By The Atkins Foundation

The study was supported by a grant from the Robert C. Atkins Foundation.

REFERENCE

Yancy WJ, Olsen M, Guyton J, Bakst R, Westman E. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Ann Intern Med. 2004 May 18, 140(10):769-77.

HOW TO GET A COPY OF THE STUDY

This study can be downloaded from:

http://www.annals.org/cgi/reprint/140/10/769.pdf

Single copies of this study may also be requested from one of the authors of the study:

Eric C. Westman, MD, MHS
Duke University Medical Center
Box 50, Suite 200-B Wing
2200 West Main Street, Durham, NC 27705
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Articles on the same subject can be found here:

• Cholesterol

• High-Protein / Low-Carb Diets

• Low Carbohydrate Diets

• Low Fat Diets

• Protein, High, Diet