Low-carbohydrate or low-fat diets for the metabolic syndrome?

Effect of various diets on biomarkers of the metabolic syndrome

The impact of the normal whole diet in different countries and of special types of diet on the biomarkers of the metabolic syndrome (MetS) is reviewed. Diet type, specification, risk of MetS and studied biomarkers, as far as could be traced, are included. Critical points in published studies are mentioned. Description of the traditional dietary patterns for the various countries is not always well-defined and numbers of persons in the studied population are sometimes quite limited, which hamper drawing definite conclusions. Since a Nordic diet, a dietary approach to stop hypertension (DASH), and especially a Mediterranean diet are quite promising, due to its health claims, the food pattern is studied more in detail and a large spectrum of vegetarian diets are included as well. Most of the time lipid profile and high sensitive C-reactive protein (hsCRP) are the studied biomarkers in response to diet intake.

Recommended Dietary Pattern to Achieve Adherence to the American Heart Association/American College of Cardiology (AHA/ACC) Guidelines: A Scientific Statement From the American Heart Association

In 2013, the American Heart Association and American College of Cardiology published the “Guideline on Lifestyle Management to Reduce Cardiovascular Risk,” which was based on a systematic review originally initiated by the National Heart, Lung, and Blood Institute. The guideline supports the American Heart Association’s 2020 Strategic Impact Goals for cardiovascular health promotion and disease reduction by providing more specific details for adopting evidence-based diet and lifestyle behaviors to achieve those goals. In addition, the 2015–2020 Dietary Guidelines for Americans issued updated evidence relevant to reducing cardiovascular risk and provided additional recommendations for adopting healthy diet and lifestyle approaches. This scientific statement, intended for healthcare providers, summarizes relevant scientific and translational evidence and offers practical tips, tools, and dietary approaches to help patients/clients adapt these guidelines according to their sociocultural, economic, and taste preferences.

A 6-month, office-based, low-carbohydrate diet intervention in obese teens

BACKGROUND

Previous studies have shown the success of a low-carbohydrate diet (LCD) in adults. In one study, the LCD has also been shown as safe and effective in teens, the study period was only 12 weeks. Furthermore, there is no information on whether the LCD is a practical intervention in a pediatric office setting.

OBJECTIVE

The object of this study was to demonstrate the effectiveness of a LCD in obese children in a primary care pediatric setting.

DESIGN/METHODS

The study was done in 11 community pediatric practices. Children ages 12 to 18 years with a body mass index (BMI) greater than 95th percentile were put on a LCD of less than 50 grams of carbohydrate daily.

RESULTS

A total of 38 of the 63 teens finished the 6-month study and 32 (84%) lost weight (range from a gain of 5.5 kg to a loss of 23.9 kg). There was also a significant decrease in mean BMI (34.9 to 32.5).

CONCLUSIONS

The LCD appears to an effective and practical office-based intervention in obese teenagers.

Exercise based lifestyle intervention in obese adults: results of the intervention study m.o.B.I.L.I.s

INTRODUCTION

Obesity is one of the greatest public health challenges of the 21st century. A combination of diet and exercise interventions have been shown to deliver stable weight reduction. M.O.B.I.L.I.S. is an interdisciplinary lifestyle modification program, aimed at lasting modification of exercise levels and diet with a view to an energy balanced lifestyle and healthy living skills.

METHODS

Lifestyle changes are to be achieved via a 12-month exercise based intervention. This standardized training program is to be followed up at predetermined time intervals in a planned sample size of 4000 to 5000 obese adults (BMI 30 to 40 kg/m(2)). As target variables body weight, body mass index, and waist circumference were defined.

RESULTS

One year results are now available for 32 groups and 454 obese participants. The results clearly demonstrate that lifestyle changes in obese individuals are possible and lead to an average weight reduction of 6.4 kg at 12 months.

DISCUSSION

M.O.B.I.L.I.S. constitutes an effective, economic, and non-pharmacological therapy option for obese adults.

The effects of a whole grain-enriched hypocaloric diet on cardiovascular disease risk factors in men and women with metabolic syndrome

BACKGROUND

Whole-grain foods are associated in observational studies with a lower body mass index and lower cardiovascular disease (CVD) risk. However, few clinical trials have tested whether incorporating whole grains into a hypocaloric diet increases weight loss and improves CVD risk factors.

OBJECTIVE

The aim of this study was to determine whether including whole-grain foods in a hypocaloric (reduced by 500 kcal/d) diet enhances weight loss and improves CVD risk factors.

DESIGN

Obese adults (25 M, 25 F) with metabolic syndrome were randomly assigned to receive dietary advice either to avoid whole-grain foods or to obtain all of their grain servings from whole grains for 12 wk. All participants were given the same dietary advice in other respects for weight loss.

RESULTS

Body weight, waist circumference, and percentage body fat decreased significantly (P<0.001) in both groups over the study period, but there was a significantly (P=0.03) greater decrease in percentage body fat in the abdominal region in the whole-grain group than in the refined-grain group. C-reactive protein (CRP) decreased 38% in the whole-grain group independent of weight loss but was unchanged in the refined-grain group (P=0.01 for group x time interaction). Total, LDL, and HDL cholesterol decreased in both diet groups (P<0.05). Dietary fiber and magnesium intakes increased in the whole-grain but not the refined-grain group (P=0.007 and P<0.001, respectively, for group x time interaction).

CONCLUSIONS

Both hypocaloric diets were effective means of improving CVD risk factors with moderate weight loss. There were significantly (P<0.05) greater decreases in CRP and percentage body fat in the abdominal region in participants consuming whole grains than in those consuming refined grains.

Increasing the fat-to-carbohydrate ratio in a high-fat diet prevents the development of obesity but not a prediabetic state in rats

Metabolic disorders induced by high-fat feeding in rodents evoke some, if not all, of the features of human metabolic syndrome. The occurrence and severity of metabolic disorders, however, varies according to rodent species, and even strain, as well as the diet. Therefore, in the present study, we investigated the long-term obesogenic and diabetogenic effects of three high-fat diets differing by their fat/carbohydrate ratios. Sprague-Dawley rats were fed a control high-carbohydrate and low-fat diet [HCD; 3:16:6 ratio of fat/carbohydrate/protein; 15.48 kJ/g (3.7 kcal/g)], a high-fat and medium-carbohydrate diet [HFD1; 53:30:17 ratio of fat/carbohydrate/protein; 19.66 kJ/g (4.7 kcal/g)], a very-high-fat and low-carbohydrate diet [HFD2; 67:9:24 ratio of fat/carbohydrate/protein; 21.76 kJ/g (5.2 kcal/g)] or a very-high-fat and carbohydrate-free diet [HFD3; 75:0:25 ratio of fat/carbohydrate/protein; 24.69 kJ/g (5.9 kcal/g)] for 10 weeks. Compared with the control diet (HCD), rats fed with high-fat combined with more (HFD1) or less (HFD2) carbohydrate exhibited higher BMI (body mass index; +13 and +10% respectively; P<0.05) and abdominal fat (+70% in both HFD1 and HFD2; P<0.05), higher plasma leptin (+130 and +135% respectively; P<0.05), lower plasma adiponectin levels (-23 and -30% respectively; P<0.05) and impaired glucose tolerance. Only the HFD1 group had insulin resistance. By contrast, a very-high-fat diet devoid of carbohydrate (HFD3) led to impaired glucose tolerance, insulin resistance and hypoadiponectinaemia (-50%; P<0.05), whereas BMI, adiposity and plasma leptin did not differ from respective values in animals fed the control diet. We conclude that increasing the fat-to-carbohydrate ratio to the uppermost (i.e. carbohydrate-free) in a high-fat diet prevents the development of obesity, but not the prediabetic state (i.e. altered glucose tolerance and insulin sensitivity).

Effects of a high walnut and high cashew nut diet on selected markers of the metabolic syndrome: a controlled feeding trial

We investigated the effects of a high walnut diet and a high unsalted cashew nut diet on selected markers of the metabolic syndrome. In a randomized, parallel, controlled study design, sixty-four subjects having the metabolic syndrome (twenty-nine men, thirty-five women) with a mean age of 45 (sd 10) years and who met the selection criteria were all fed a 3-week run-in control diet. Hereafter, participants were grouped according to gender and age and then randomized into three groups receiving a controlled feeding diet including walnuts, or unsalted cashew nuts or no nuts for 8 weeks. Subjects were required to have lunch at the metabolic ward of the Nutrition Department of the North-West University (Potchefstroom Campus). Both the walnut and the unsalted cashew nut intervention diets had no significant effect on the HDL-cholesterol, TAG, total cholesterol, LDL-cholesterol, serum fructosamine, serum high-sensitivity C-reactive protein, blood pressure and serum uric acid concentrations when compared to the control diet. Low baseline LDL-cholesterol concentrations in the cashew nut group may have masked a possible nut-related benefit. Plasma glucose concentrations increased significantly (P = 0·04) in the cashew nut group compared to the control group. By contrast, serum fructosamine was unchanged in the cashew nut group while the control group had significantly increased (P = 0·04) concentrations of this short-term marker of glycaemic control. Subjects displayed no improvement in the markers of the metabolic syndrome after following a walnut diet or a cashew nut diet compared to a control diet while maintaining body weight.