Randomised Controlled Trials - Adverse or Mixed Results
There are seven trials in this group
Concern About Cholesterol on the Low Carb Diet
Weight loss with high and low carbohydrate 1200 kcal diets in free living women (1997)
MEJ Lean, TS Han, T Prvan, PR Richmond & A Avenell
Conclusions: On the high CHO diet, total cholesterol remained significantly below the baseline value at 0.34 mmol/l, triglyceride was significantly lowered by 0.27 mmol/l, and HDL cholesterol returned to the baseline value. On the low CHO diet, triglyceride remained the only risk factor to be significantly improved. A subgroup of 46 postmenopausal women lost significantly more weight on the low CHO diet than high CHO diet. In conclusion, these results provided some support for preferring a high CHO diet to a lower CHO approach in weight management, from the point of view of risk reduction, but do not indicate a consistently more rapid weight loss with either diet.
Concern About Cholesterol
The effect of a plant-based diet on plasma lipids in hypercholesterolemic adults (2005)
Gardner CD, Coulston A, Chatterjee L, Rigby A, Spiller G, Farquhar JW
120 adults 30 to 65 years of age. Prestudy low‐density lipoprotein (LDL) cholesterol concentrations of 3.3 to 4.8 mmol/L (130 to 190 mg/dL) (eg High LDL-C)
Two diets, the Low‐Fat diet and the Low‐Fat Plus diet, designed to be identical in total fat, saturated fat, protein, carbohydrate, and cholesterol content.
The Low‐Fat Plus diet incorporated considerably more vegetables, legumes, and whole grains.
Conclusions: Previous national dietary guidelines primarily emphasized avoiding saturated fat and cholesterol; as a result, the guidelines probably underestimated the potential LDL cholesterol‐lowering effect of diet. In this study, emphasis on including nutrient‐dense plant‐based foods, consistent with recently revised national guidelines, increased the total and LDL cholesterol‐lowering effect of a low‐fat diet.
Adverse Study ? - Not Low Carb. - Worried About Saturated Fats
Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia (2006)
Ronald M Krauss, Patricia J Blanche, Robin S Rawlings, Harriett S Fernstrom, Paul T Williams
178 men with a mean body mass index (in kg/m2) of 29.2 ± 2.0
Randomly assigned to consume one of four diets: Three with carbohydrate contents of 54% (basal diet), 39%, or 26% of energy and with a low saturated fat content (7–9% of energy);
The fourth group consumed a diet with 26% of energy as carbohydrate and 15% as saturated fat.
Conclusions: Moderate carbohydrate restriction and weight loss provide equivalent but nonadditive approaches to improving atherogenic dyslipidemia. Moreover, beneficial lipid changes resulting from a reduced carbohydrate intake were not significant after weight loss.
NOTE: This was a moderate carbohydrate restriction only. Two groups with carbohydrate restricted to 26% of calories. One with more fat than the other. Read the results for yourself. I find them confusing.
Testing Orlistat v a Low Carb Diet
A randomized trial of a low-carbohydrate diet vs Orlistat plus a low-fat diet for weight loss (2010)
William S Yancy Jr, Eric C Westman, Jennifer R McDuffie, Steven C Grambow, Amy S Jeffreys, Jamiyla Bolton, Allison Chalecki, Eugene Z Oddone
Overweight or obese outpatients (n = 146). The mean age was 52 years.
randomized to either LCKD instruction (initially, less than 20 g of carbohydrate daily) or orlistat therapy, 120 mg orally 3 times daily, plus low‐fat diet instruction (Less than 30% energy from fat, 500‐1000 kcal/d deficit)
"Orlistat", is a gastrointestinal lipase inhibitor.
Conclusions: In a sample of medical outpatients, an LCKD led to similar improvements as O + LFD for weight, serum lipid, and glycemic parameters and was more effective for lowering blood pressure.
Adverse Result - No Weight Loss + High LDL-C + High Triglycerides
Teri L Hernandez, Julie P Sutherland, Pamela Wolfe, Marybeth Allian-Sauer, Warren H Capell, Natalie D Talley, Holly R Wyatt, Gary D Foster, James O Hill, Robert H Eckel
Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet (Less than 20 gm per day and high fat.), or a calorie-restricted, low-fat diet (56% carbohydrate and low fat.) for 6 weeks.
Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times.
Conclusions: Our data indicate that a high-fat diet, increased LDL-cholesterol concentrations over 6 weeks, and that this effect related at least in part to the lack of suppression of both fasting Free Fatty Acids and FFA measured hourly for 24 hr. Despite this adverse effect, weight loss was not greater in the High Fat group. Thus, these data suggest that a high-fat diet may have adverse metabolic effects during active weight loss.
NOTE: There is a very long and interesting discussion to end this study. People randomly assigned to a diet usually hate it; there is no discussion of dropouts. Restriction to 20 gm/d of carbohydrate is very severe, and there is no discussion of ketone production. If participants were not in ketosis that would explain why the free fatty acids were so high. Lots of questions in my mind.
No Significant Weight Loss
Nayyar Iqbal, Marion L. Vetter, Reneé H. Moore, Jesse L. Chittams, Cornelia V. Dalton-Bakes, Monique Dowd, Catherine Williams-Smith, Serena Cardillo, Thomas A. Wadden
Conclusions: We found no significant differences at 24 months in weight, glycemic control, lipid levels, or dietary intake between low-carbohydrate and low-fat diets that were delivered in a low-intensity intervention, consistent with the limitations of primary care practice. Better dietary adherence and greater weight loss might be achieved in combination with a higher-intensity intervention.
NOTE: The target carbohydrate intake was 30 g/day. Ketones were not measured.
No Reduction of Insulin Resistance
Christopher D. Gardner, Lisa C. Offringa, Jennifer C. Hartle, Kris Kapphahn, Rise Cherin
Conclusions: Substantial weight loss was achieved overall, but a significant diet × IR status interaction was not observed. Opportunity to detect differential response may have been limited by the focus on high diet quality for both diet groups and sample size.
NOTE: Carbohydrate 22% of diet.
