A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women

Untested alternative weight loss diets, such as very low carbohydrate diets, have unsubstantiated efficacy and the potential to adversely affect cardiovascular risk factors. Therefore, we designed a randomized, controlled trial to determine the effects of a very low carbohydrate diet on body composition and cardiovascular risk factors. Subjects were randomized to 6 months of either an ad libitum very low carbohydrate diet or a calorie-restricted diet with 30% of the calories as fat. Anthropometric and metabolic measures were assessed at baseline, 3 months, and 6 months. Fifty-three healthy, obese female volunteers (mean body mass index, 33.6 +/- 0.3 kg/m(2)) were randomized; 42 (79%) completed the trial. Women on both diets reduced calorie consumption by comparable amounts at 3 and 6 months. The very low carbohydrate diet group lost more weight (8.5 +/- 1.0 vs. 3.9 +/- 1.0 kg; P < 0.001) and more body fat (4.8 +/- 0.67 vs. 2.0 +/- 0.75 kg; P < 0.01) than the low fat diet group. Mean levels of blood pressure, lipids, fasting glucose, and insulin were within normal ranges in both groups at baseline. Although all of these parameters improved over the course of the study, there were no differences observed between the two diet groups at 3 or 6 months. beta- Hydroxybutyrate increased significantly in the very low carbohydrate group at 3 months (P = 0.001). Based on these data, a very low carbohydrate diet is more effective than a low fat diet for short-term weight loss and, over 6 months, is not associated with deleterious effects on important cardiovascular risk factors in healthy women.     

Long‐term effects of weight loss with a very low carbohydrate and low fat diet on vascular function in overweight and obese patients

Abstract. Wycherley TP, Brinkworth GD, Keogh JB, Noakes M, Buckley JD, Clifton PM. (Commonwealth Scientific and Industrial Research Organization, Food and Nutritional Sciences; School of Molecular and Biomedical Science, University of Adelaide; and Nutritional Physiology Research Centre and Australian Technology Network Centre for Metabolic Fitness, Sansom Institute for Health Research, University of South Australia). Long‐term effects of weight loss with a very low carbohydrate and low fat diet on vascular function in overweight and obese patients. J Intern Med 2010; 267 : 452–461. Objective. To compare the effects of an energy reduced very low carbohydrate, high saturated fat diet (LC) and an isocaloric high carbohydrate, low fat diet (LF) on endothelial function after 12 months. Design and Subjects. Forty‐nine overweight or obese patients (age 50.0 ± 1.1 years, BMI 33.7 ± 0.6 kg m^?2) were randomized to either an energy restricted (～6–7 MJ), planned isocaloric LC or LF for 52 weeks. Body weight, endothelium‐derived factors, flow‐mediated dilatation (FMD), adiponectin, augmentation index (AIx) and pulse wave velocity (PWV) were assessed. All data are mean ± SEM. Results. Weight loss was similar in both groups (LC ?14.9 ± 2.1 kg, LF ?11.5 ± 1.5 kg; P = 0.20). There was a significant time × diet effect for FMD (P = 0.045); FMD decreased in LC (5.7 ± 0.7% to 3.7 ± 0.5%) but remained unchanged in LF (5.9 ± 0.5% to 5.5 ± 0.7%). PWV improved in both groups (LC ?1.4 ± 0.6 m s^?1, LF ?1.5 ± 0.6 m s^?1; P = 0.001 for time) with no diet effect (P = 0.80). AIx and VCAM‐1 did not change in either group. Adiponectin, eSelectin, tPA and PAI‐1 improved similarly in both groups (P < 0.01 for time). Conclusion. Both LC and LF hypoenergetic diets achieved similar reductions in body weight and were associated with improvements in PWV and a number of endothelium‐derived factors. However, the LC diet impaired FMD suggesting chronic consumption of a LC diet may have detrimental effects on endothelial function.     

Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial

BACKGROUND: Despite the popularity of low-glycemic index (GI) and high-protein diets, to our knowledge no randomized, controlled trials have systematically compared their relative effects on weight loss and cardiovascular risk. METHODS: A total of 129 overweight or obese young adults (body mass index, > or =25 [calculated as weight in kilograms divided by the square of height in meters]) were assigned to 1 of 4 reduced-fat, high-fiber diets for 12 weeks. Diets 1 and 2 were high carbohydrate (55% of total energy intake), with high and low GIs, respectively; diets 3 and 4 were high protein (25% of total energy intake), with high and low GIs, respectively. The glycemic load was highest in diet 1 and lowest in diet 4. Changes in weight, body composition, and blood chemistry profile were studied. RESULTS: While all groups lost a similar mean +/- SE percentage of weight (diet 1, -4.2% +/- 0.6%; diet 2, -5.5% +/- 0.5%; diet 3, -6.2% +/- 0.4%; and diet 4, -4.8% +/- 0.7%; P = .09), the proportion of subjects in each group who lost 5% or more of body weight varied significantly by diet (diet 1, 31%; diet 2, 56%; diet 3, 66%; and diet 4, 33%; P = .01). Women on diets 2 and 3 lost approximately 80% more fat mass (-4.5 +/- 0.5 [mean +/- SE] kg and -4.6 +/- 0.5 kg) than those on diet 1 (-2.5 +/- 0.5 kg; P = .007). Mean +/- SE low-density-lipoprotein cholesterol levels declined significantly in the diet 2 group (-6.6 +/- 3.9 mg/dL [-0.17 +/- 0.10 mmol/L]) but increased in the diet 3 group (+10.0 +/- 3.9 mg/dL [+0.26 +/- 0.10 mmol/L]; P = .02). Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat, and the diet 2 group ate more fiber. CONCLUSION: Both high-protein and low-GI regimens increase body fat loss, but cardiovascular risk reduction is optimized by a high-carbohydrate, low-GI diet.     

Effects of weight loss medications on mortality and cardiovascular events: A systematic review of randomized controlled trials in adults with overweight and obesity

AimsAdults affected by obesity are at higher risk of premature mortality. Medications can help to lose weight and to maintain weight loss. Aim of this meta-analysis was to assess whether anti-obesity medications affect all-cause mortality, mortality due to cardiovascular events, cardiovascular risk factors and body weight.Data synthesisA Medline search was performed to identify randomized controlled trials (RCTs) of anti-obesity medications in adults with overweight or obesity reporting data on all-cause mortality, cardiovascular mortality or non-fatal cardiovascular events, with a follow-up of at least 6 months. We identified 28 RCTs with 50,106 participants. The median follow-up was 52 weeks. Evidence did not show superiority of anti-obesity medications over placebo in reducing all-cause mortality (risk ratio 1.03, 95%Confidence Interval [CI] 0.87 to 1.21) or cardiovascular mortality (risk ratio 0.92, 95%CI 0.72 to 1.18). All-cause mortality rate was positively associated with weight loss (β = 0.0007; p = 0.045); hence, for each kg of body weight lost there was a 0.07% decrease of all-cause mortality. The pharmacological treatment reduced total-cholesterol (7.15 mg/dl; 95%CI 1.46–12.85), LDL-cholesterol (5.06 mg/dl; 95%CI 1.12–9.00), and triglycerides levels (9.88 mg/dl; 95%CI 5.02–14.75), while it increased HDL-cholesterol (1.37 mg/dl; 95%CI 0.17–2.57). Systolic blood pressure decreased (0.90 mmHg; 95%CI 0.15–1.64).ConclusionsAlthough we were unable to demonstrate a superiority of anti-obesity medications over placebo on mortality, metaregression showed that even a small weight reduction tends to reduce all-cause mortality in obesity. Our data support public health measures to reduce the obesity burden by including the use of anti-obesity medications.Registration number (PROSPERO)CRD42020210329.     

A randomized controlled trial of high versus low intensity weight training versus general practitioner care for clinical depression in older adults

BACKGROUND: Although exercise has been shown to relieve depression, little is known about its mechanism or dose-response characteristics. We hypothesized that high intensity progressive resistance training (PRT) would be more effective than either low intensity PRT or standard care by a general practitioner (GP) in depressed elderly persons, and that high intensity PRT would provide superior benefits in quality of life, sleep quality, and self-efficacy. METHODS: Sixty community-dwelling adults >60 years with major or minor depression were randomized to supervised high intensity PRT (80% maximum load) or low intensity PRT (20% maximum load) 3 days per week for 8 weeks, or GP care. RESULTS: A 50% reduction in the Hamilton Rating Scale of Depression score was achieved in 61% of the high intensity, 29% of the low intensity, and 21% of the GP care group (p =.03). Strength gain was directly associated with reduction in depressive symptoms (r = 0.40, p =.004), as was baseline social support network type (F = 3.52, p =.015), whereas personality type, self-efficacy, and locus of control were unrelated to the antidepressant effect. Vitality quality-of-life scale improved more in the high intensity group than in the others (p =.04). Sleep quality improved significantly in all participants (p <.0001), with the greatest relative change in high intensity PRT (p =.05). CONCLUSIONS: High intensity PRT is more effective than is low intensity PRT or GP care for the treatment of older depressed patients.     

Bone mineral density response to caloric restriction-induced weight loss or exercise-induced weight loss: a randomized controlled trial

BACKGROUND: Bone loss often accompanies weight loss induced by caloric restriction (CR), but whether bone loss accompanies similar weight loss induced by exercise (EX) is unknown. We tested the hypothesis that EX-induced weight loss is associated with less bone loss compared with CR-induced weight loss. METHODS: Forty-eight adults (30 women; 18 men; mean +/- SD age, 57 +/- 3 years; and mean +/- SD body mass index, 27 +/- 2 kg/m2) were randomized to 1 of 3 groups for 1 year: CR group (n = 19), regular EX group (n = 19), or a healthy lifestyle (HL) control group (n = 10). Primary outcome measure was change in hip and spine bone mineral density (BMD). Secondary outcomes were bone markers and hormones. RESULTS: Body weight decreased similarly in the CR and EX groups (10.7% +/- 6.3% [-8.2 +/- 4.8 kg] vs 8.4% +/- 6.3% [-6.7 +/- 5.6 kg]; P = .21), whereas weight did not change in the HL group (-1.2% +/- 2.5% [-0.9 +/- 2.0 kg]). Compared with the HL group, the CR group had decreases in BMD at the total hip (-2.2% +/- 3.1% vs 1.2% +/- 2.1%; P = .02) and intertrochanter (-2.1% +/- 3.4% vs 1.7 +/- 2.8%; P = .03). The CR group had a decrease in spine BMD (-2.2% +/- 3.3%; P = .009). Despite weight loss, the EX group did not demonstrate a decrease in BMD at any site. Body weight changes correlated with BMD changes in the CR (R = 0.61; P = .007) but not in the EX group. Bone turnover increased in both CR and EX groups. CONCLUSIONS: CR-induced weight loss, but not EX-induced weight loss, is associated with reductions in BMD at clinically important sites of fracture. These data suggest that EX should be an important component of a weight loss program to offset adverse effects of CR on bone.     

The effect of two energy-restricted diets, a low-fructose diet versus a moderate natural fructose diet, on weight loss and metabolic syndrome parameters: a randomized controlled trial

One of the proposed causes of obesity and metabolic syndrome is the excessive intake of products containing added sugars, in particular, fructose. Although the ability of excessive intake of fructose to induce metabolic syndrome is mounting, to date, no study has addressed whether a diet specifically lowering fructose but not total carbohydrates can reduce features of metabolic syndrome. A total of 131 patients were randomized to compare the short-term effects of 2 energy-restricted diets—a low-fructose diet vs a moderate natural fructose diet—on weight loss and metabolic syndrome parameters. Patients were randomized to receive 1500, 1800, or 2000 cal diets according to sex, age, and height. Because natural fructose might be differently absorbed compared with fructose from added sugars, we randomized obese subjects to either a low-fructose diet (<20 g/d) or a moderate-fructose diet with natural fruit supplements (50-70 g/d) and compared the effects of both diets on the primary outcome of weight loss in a 6-week follow-up period. Blood pressure, lipid profile, serum glucose, insulin resistance, uric acid, soluble intercellular adhesion molecule-1, and quality of life scores were included as secondary outcomes. One hundred two (78%) of the 131 participants were women, mean age was 38.8 ± 8.8 years, and the mean body mass index was 32.4 ± 4.5 kg/m². Each intervention diet was associated with significant weight loss compared with baseline. Weight loss was higher in the moderate natural fructose group (4.19 ± 0.30 kg) than the low-fructose group (2.83 ± 0.29 kg) (P = .0016). Compared with baseline, each intervention diet was associated with significant improvement in secondary outcomes. Reduction of energy and added fructose intake may represent an important therapeutic target to reduce the frequency of obesity and diabetes. For weight loss achievement, an energy-restricted moderate natural fructose diet was superior to a low-fructose diet.     

A controlled trial of a high fibre,low fat and low sodium diet for mild hypertension in type 2 (non-insulin-dependent) diabetic patients

Summary Fifty hypertensive Type 2 (non-insulin-dependent) diabetic patients were allocated, in a controlled trial, to a treatment diet of high fibre, low fat and low sodium composition, or to a control diet by the hospital dietitian. After 3 months treatment, the modified diet-treated group showed a highly significant reduction in mean systolic (180.5±19.0 to 165.0±20.7 mmHg) and diastolic blood pressure (96.6±9.3 to 88.0±10.5 mmHg), accompanied by significant reductions in urinary sodium excretion (183.0±62.1 to 121.7+ 65.8 mmol/day) glycosylated haemoglobin (12.4±3.1 to 10.5±2.9%), weight (74.6s±13.5 to 71.7±12.1 kg) and serum triglyceride levels (p<0.05). The mean values of diastolic pressure (p<0.01), urinary sodium/potassium ratio (p< 0.001), urinary potassium (p<0.01) was significantly reduced at 3 months compared to control. No changes in serum HDL-cholesterol levels were observed. The number of patients with normal blood pressure at 3 months was greater in the modified diet-treated group (ten versus five). Treatment of mild hypertension in diabetic subjects with this form of dietary regimen has a hypotensive response, with improvement in glycaemic control and no side effects. This modified diet may be an attractive alternative to anti-hypertensive drug therapy as a first line treatment.