The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One-Year Follow-up of a Randomized Trial Linda Stern, MD; Nayyar Iqbal, MD; Prakash Seshadri, MD; Kathryn L. Chicano, CRNP; Denise A. Daily, RD; Joyce McGrory, CRNP; Monica Williams, BS; Edward J. Gracely, PhD; and Frederick F. Samaha, MD 18 May 2004 | Volume 140 Issue 10 | Pages 778-785 Background: A previous paper reported the 6-month comparison of weight loss and metabolic changes in obese adults randomly assigned to either a low-carbohydrate diet or a conventional weight loss diet. Objective: To review the 1-year outcomes between these diets. Design: Randomized trial. Setting: Philadelphia Veterans Affairs Medical Center. Participants: 132 obese adults with a body mass index of 35 kg/m2 or greater; 83% had diabetes or the metabolic syndrome. Intervention: Participants received counseling to either restrict carbohydrate intake to <30 g per day (low-carbohydrate diet) or to restrict caloric intake by 500 calories per day with <30% of calories from fat (conventional diet).   Measurements: Changes in weight, lipid levels, glycemic control, and insulin sensitivity. Results: By 1 year, mean (±SD) weight change for persons on the low-carbohydrate diet was –5.1 ± 8.7 kg compared with –3.1 ± 8.4 kg for persons on the conventional diet. Differences between groups were not significant (–1.9 kg [95% CI, –4.9 to 1.0 kg]; P = 0.20). For persons on the low-carbohydrate diet, triglyceride levels decreased more (P = 0.044) and high-density lipoprotein cholesterol levels decreased less (P = 0.025). As seen in the small group of persons with diabetes (n = 54) and after adjustment for covariates, hemoglobin A1c levels improved more for persons on the low-carbohydrate diet. These more favorable metabolic responses to a low-carbohydrate diet remained significant after adjustment for weight loss differences. Changes in other lipids or insulin sensitivity did not differ between groups. Limitations: These findings are limited by a high dropout rate (34%) and by suboptimal dietary adherence of the enrolled persons. Conclusion: Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on atherogenic dyslipidemia and glycemic control were still more favorable with a low-carbohydrate diet after adjustment for differences in weight loss A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia A Randomized, Controlled Trial William S. Yancy, Jr., MD, MHS; Maren K. Olsen, PhD; John R. Guyton, MD; Ronna P. Bakst, RD; and Eric C. Westman, MD, MHS 18 May 2004 | Volume 140 Issue 10 | Pages 769-777 Background: Low-carbohydrate diets remain popular despite a paucity of scientific evidence on their effectiveness. Objective: To compare the effects of a low-carbohydrate, ketogenic diet program with those of a low-fat, low-cholesterol, reduced-calorie diet. Design: Randomized, controlled trial. Setting: Outpatient research clinic. Participants: 120 overweight, hyperlipidemic volunteers from the community. Intervention: Low-carbohydrate diet (initially, <20 g of carbohydrate daily) plus nutritional supplementation, exercise recommendation, and group meetings, or low-fat diet (<30% energy from fat, <300 mg of cholesterol daily, and deficit of 500 to 1000 kcal/d) plus exercise recommendation and group meetings. Measurements: Body weight, body composition, fasting serum lipid levels, and tolerability. Results: A greater proportion of the low-carbohydrate diet group than the low-fat diet group completed the study (76% vs. 57%; P = 0.02). At 24 weeks, weight loss was greater in the low-carbohydrate diet group than in the low-fat diet group (mean change, –12.9% vs. –6.7%; P < 0.001). Patients in both groups lost substantially more fat mass (change, –9.4 kg with the low-carbohydrate diet vs. –4.8 kg with the low-fat diet) than fat-free mass (change, –3.3 kg vs. –2.4 kg, respectively). Compared with recipients of the low-fat diet, recipients of the low-carbohydrate diet had greater decreases in serum triglyceride levels (change, –0.84 mmol/L vs. –0.31 mmol/L [–74.2 mg/dL vs. –27.9 mg/dL]; P = 0.004) and greater increases in high-density lipoprotein cholesterol levels (0.14 mmol/L vs. –0.04 mmol/L [5.5 mg/dL vs. –1.6 mg/dL]; P < 0.001). Changes in low-density lipoprotein cholesterol level did not differ statistically (0.04 mmol/L [1.6 mg/dL] with the low-carbohydrate diet and –0.19 mmol/L [–7.4 mg/dL] with the low-fat diet; P = 0.2). Minor adverse effects were more frequent in the low-carbohydrate diet group. Limitations: We could not definitively distinguish effects of the low-carbohydrate diet and those of the nutritional supplements provided only to that group. In addition, participants were healthy and were followed for only 24 weeks. These factors limit the generalizability of the study results. Conclusions: Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.

Sugar-Sweetened Beverages, Weight Gain, and Incidence of Type 2 Diabetes in Young and Middle-Aged Women

Reference:
Schulze, M.B., Manson, J.E., Ludwig, D.S., et al., "Sugar-Sweetened Beverages, Weight Gain, and Incidence of Type 2 Diabetes in Young and Middle-Aged Women," Journal of the American Medical Association, 292(8), 2004, pages 927-934.

Summary:

The following information is available at Pub Med and was not written by Atkins professionals.

CONTEXT: Sugar-sweetened beverages like soft drinks and fruit punches contain large amounts of readily absorbable sugars and may contribute to weight gain and an increased risk of type 2 diabetes, but these relationships have been minimally addressed in adults.

OBJECTIVE: To examine the association between consumption of sugar-sweetened beverages and weight change and risk of type 2 diabetes in women.

DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort analyses conducted from 1991 to 1999 among women in the Nurses' Health Study II. The diabetes analysis included 91,249 women free of diabetes and other major chronic diseases at baseline in 1991. The weight change analysis included 51,603 women for whom complete dietary information and body weight were ascertained in 1991, 1995, and 1999. We identified 741 incident cases of confirmed type 2 diabetes during 716,300 person-years of follow-up.

MAIN OUTCOME MEASURES: Weight gain and incidence of type 2 diabetes.

RESULTS: Those with stable consumption patterns had no difference in weight gain, but weight gain over a 4-year period was highest among women who increased their sugar-sweetened soft drink consumption from 1 or fewer drinks per week to 1 or more drinks per day (multivariate-adjusted means, 4.69 kg for 1991 to 1995 and 4.20 kg for 1995 to 1999) and was smallest among women who decreased their intake (1.34 and 0.15 kg for the 2 periods, respectively) after adjusting for lifestyle and dietary confounders. Increased consumption of fruit punch was also associated with greater weight gain compared with decreased consumption. After adjustment for potential confounders, women consuming 1 or more sugar-sweetened soft drinks per day had a relative risk [RR] of type 2 diabetes of 1.83 (95% confidence interval [CI], 1.42-2.36; P<.001 for trend) compared with those who consumed less than 1 of these beverages per month. Similarly, consumption of fruit punch was associated with increased diabetes risk (RR for > or =1 drink per day compared with <1 drink per month, 2.00; 95% CI, 1.33-3.03; P =.001).

CONCLUSION: Higher consumption of sugar-sweetened beverages is associated with a greater magnitude of weight gain and an increased risk for development of type 2 diabetes in women, possibly by providing excessive calories and large amounts of rapidly absorbable sugars.

Carbohydrates and the Risk of Breast Cancer among Mexican Women

Reference:
Romieu, I., Lazcano-Ponce, E., Sanchez-Zamorano, L.M., et al., "Carbohydrates and the Risk of Breast Cancer among Mexican Women," Cancer Epidemiology, Biomarkers and Prevention, 13(8), 2004, pages 1283-1289.

Summary:

The following information is available at Pub Med and was not written by Atkins professionals.

OBJECTIVE: High carbohydrate intake has been hypothesized to be a risk factor for breast cancer, possibly mediated by elevated levels of free insulin, estrogens, and insulin-like growth factor-1. Therefore, we conducted a population-based case-control study among a Mexican population characterized by relatively low fat and high carbohydrate intakes.

METHODS: Women ages 20 to 75 years, identified through six hospitals in Mexico City (n = 475), were interviewed to obtain data relating to diet (using a food frequency questionnaire) and breast cancer risk factors. Controls (n = 1,391) were selected from the Mexico City population using a national sampling frame.

RESULTS: Carbohydrate intake was positively associated with breast cancer risk. Compared with women in the lowest quartile of total carbohydrate intake, the relative risk of breast cancer for women in the highest quartile was 2.22 [95% confidence interval (95% CI) 1.63-3.04], adjusting for total energy and potential confounding variables (P for trend < 0.0001). This association was present in premenopausal and postmenopausal women (for highest versus lowest quartile, odds ratio 2.31, 95% CI 1.36-3.91 in premenopausal women and odds ratio 2.22, 95% CI 1.49-3.30 in postmenopausal women). Among carbohydrate components, the strongest associations were observed for sucrose and fructose. No association was observed with total fat intake.

DISCUSSION: In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk. This relation deserves to be investigated further, particularly in populations highly susceptible to insulin resistance.

Weight Loss Leads to Reductions in Inflammatory Biomarkers

Reference:
Sharman, M.J., Volek, J.S., "Weight Loss Leads to Reductions in Inflammatory Biomarkers after a Very Low-Carbohydrate and Low-Fat Diet in Overweight Men," Clinical Science (London), 2004.

Summary:

The following information is available at Pub Med and was not written by Atkins professionals.

In recent years, it has become apparent that low-grade vascular inflammation plays a key role in all stages of the pathogenesis of atherosclerosis. Weight loss has been shown to improve blood inflammatory markers; however, it is unknown if weight loss diets varying in macronutrient composition differentially affect inflammatory responses. The primary purpose of this study was to compare a very low-carbohydrate and a low-fat weight loss diet on inflammatory biomarkers in overweight men. In a randomized cross-over design, fifteen overweight men (body fat >25%, body mass index 34 kg/m 2) consumed two experimental weight loss diets for 2 consecutive 6 wk periods: a very low-carbohydrate (<10% energy carbohydrate) and a low-fat (<30% energy fat) diet. Both the low-fat and the very low-carbohydrate diet resulted in significant decreases in absolute concentrations of hsTNF-alpha, hsIL-6, hs-CRP and sICAM-1. There was no significant change in absolute sP-selectin concentrations after either diet. Normalized inflammatory values represented as the delta change per one kilogram reduction in body mass showed a significant difference between the two diets only for sP-selectin (P<0.05). In summary, energy-restricted low-fat and very low-carbohydrate diets both significantly decreased several biomarkers of inflammation. These data suggest that in the short-term weight loss is primarily the driving force underlying the reductions in most of the inflammatory biomarkers.

Diet Therapy for Narcolepsy

Reference:
Husain, A.M., Yancy, W.S., Jr., Carwile, S.T., et al., "Diet Therapy for Narcolepsy," Neurology, 62(12), 2004, pages 2300-2302.

Summary:

The following information is available at Pub Med and was not written by Atkins professionals.

The effects of a low-carbohydrate, ketogenic diet (LCKD) on sleepiness and other narcolepsy symptoms were studied. Nine patients with narcolepsy were asked to adhere to the Atkins' diet plan, and their symptoms were assessed using the Narcolepsy Symptom Status Questionnaire (NSSQ). The NSSQ-Total score decreased by 18% from 161.9 to 133.5 (p = 0.0019) over 8 weeks. Patients with narcolepsy experienced modest improvements in daytime sleepiness on an LCKD.

 

High-Protein Weight Loss Diets and Purported Adverse Effects: Where is the Evidence

Reference:
Manninen, A.H., “High-Protein Weight Loss Diets and Purported Adverse Effects:  Where is the Evidence,” Sports Nutrition Review Journal, 2004, 1(1), pages 45-51.

Summary:

The following information was written by Atkins professionals.

This review article evaluated the literature regarding the effects of high-protein, low-carbohydrate weight loss diets on cardiac, renal, bone, and liver functions. Over 40 studies were examined.  A variety of populations were investigated including pre- and post-menopausal women, body builders, diabetics, patients with recent hip fractures, and the elderly. Only studies which examined individuals with normal kidney function were considered for this review. According to the studies evaluated, there is no evidence suggesting protein is associated with reduced cardiac function. In fact, there are studies which actually support that risk of heart disease is lower and blood lipid concentrations are more favorable when dietary protein replaces carbohydrate.  Several studies have shown a negative correlation between protein intake and blood pressures. There is no data indicating that a healthy kidney will be damaged when consuming protein levels above the Recommended Dietary Allowance (RDA).  While the long-term effect of a high protein intake on renal function in diabetics has not been determined, improvements in overall blood sugar control and the lipid profile has been observed over the short term. Although there is an increase in urinary calcium excretion when consuming more dietary protein, calcium is not leached from the bone.  High protein intake has actually been associated with increasing bone mineral density and a lower risk of osteoporosis.  There is no scientific evidence supporting that high protein intake is associated with detrimental effects on liver function.  For individuals with normal kidney function, high protein diets are safe and may offer additional health benefits.

 

Premenopausal Women Following a Low-Carbohydrate/High-Protein Diet Experience Greater Weight Loss and Less Hunger Compared to a High-Carbohydrate/Low-Fat Diet

Reference:
Nickols-Richardson, S.M., Volpe, J.J., Coleman, M.D., “Premenopausal Women Following a Low-Carbohydrate/High-Protein Diet Experience Greater Weight Loss and Less Hunger Compared to a High-Carbohydrate/Low-Fat Diet,”  Abstract Presented at FASEB Meeting on Experimental Biology:  Translating the Genome, April 17-21, 2004, in Washington, D.C.

Summary:

The following information was written by Atkins professionals.

Premenopausal women were instructed to follow either a low carbohydrate/high protein diet (20 grams of carbohydrate per day) increasing carbohydrate by 5 grams per week, or a high carbohydrate/low fat diet (150 grams of carbohydrate, 30% energy from fat) for six weeks.  Both groups lost a significant amount of weight from before they began the diet, but the 14 women on the low carbohydrate diet lost significantly more than the 15 women on the high carbohydrate diet (14.8% vs 4.3% body weight).  Both groups reported having a significantly greater amount of eating restraint than before they began the diet.  Only in the low carbohydrate group did hunger scores decrease significantly.  Although women in both groups had weight loss success, a low carbohydrate diet appears to be superior to a higher carbohydrate diet as it results in greater percent change in body weight with lower scores in hunger.

Commentary:

The following information was written by Atkins professionals.

 A low carbohydrate/high protein diet produced greater weight loss than a high carbohydrate/low fat diet. This could be related to how the women on the low carbohydrate diet reported being significantly less hungry than the women on the higher carbohydrate diet, as being less hungry would make it easier to adhere to diet guidelines. These results suggest that women may experience greater benefits following a low carbohydrate diet than a high carbohydrate diet.

High-carb diets may increase cancer risk


by Liz Szabo | Feb 04 '04

Diets filled with certain high-carbohydrate foods may increase the risk of colorectal cancer in women, according to a study published today in the Journal of the National Cancer Institute .

Cakes, cookies and other quickly digested foods score high on the "glycemic index," a measure of the rate at which carbohydrates are processed into sugar.

A sudden surge in blood sugar prompts the body to produce a matching rush of insulin, which helps convert the sugar, or glucose, into energy. Insulin stimulates cells to divide and keeps them alive longer than normal. That could encourage the growth of tumors, the study says.

Brown rice and wheat breads, in contrast, contain carbs that are absorbed more slowly by the body.

Researchers at Harvard Medical School and Brigham and Women's Hospital in Boston followed more than 38,000 women for an average of nearly eight years and identified 174 with colorectal cancer, according to the article. Women in the study with high dietary glycemic loads were more than twice as likely to develop colorectal cancer.

Some health experts say the study, although preliminary, is intriguing.

"You may pay for that sugar high in more ways than you realize," said Michael Thun, head of epidemiologic research for the American Cancer Society.

He noted that results of similar studies have been mixed, however, and that more research is needed.

Others note that measuring glycemic loads is complicated.

"It's difficult for the average person to make sense of this," said dietitian Melanie Polk, director of nutritional education for the American Institute for Cancer Research. "An easier guide is to base your diet on fruits, vegetables, beans and whole grains."