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Effects of Low-Carbohydrate versus Mediterranean Diets on Weight Loss, Glucose Metabolism, Insulin Kinetics and β-Cell Function in Morbidly Obese Individuals.
Tricò, D, Moriconi, D, Berta, R, Baldi, S, Quinones-Galvan, A, Guiducci, L, Taddei, S, Mari, A, Nannipieri, M
Nutrients. 2021;13(4)
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Both low-carbohydrate and Mediterranean style diets are used to prevent lifestyle associated diseases such as obesity and type 2 diabetes. However, which diet is more effective is unclear. The aim of this randomised control trial of 36 morbidly obese individuals was to compare the effectiveness of Mediterranean diets and low-carbohydrate diets to improve metabolic measures such as blood sugar levels, pre-diabetes, and the body’s ability to use sugar. The results showed that in the short-term both diets were equally effective at improving biochemical dysfunctions that contribute to type 2 diabetes. The low-carbohydrate diet did result in higher weight loss than the Mediterranean diet. Studies on long-term effects are warranted. It was concluded that a low-carbohydrate diet is in the short-term a feasible alternative to the Mediterranean diet for improved weight loss and biological contributors to type 2 diabetes. This study could be used by healthcare professionals to understand that the Mediterranean diet and low-carbohydrate diet are both effective in the short-term for improvements to contributors to type 2 diabetes, however the low-carbohydrate diet may be superior if weight loss is required.
Abstract
Low-calorie Mediterranean-style or low-carbohydrate dietary regimens are widely used nutritional strategies against obesity and associated metabolic diseases, including type 2 diabetes. The aim of this study was to compare the effectiveness of a balanced Mediterranean diet with a low-carbohydrate diet on weight loss and glucose homeostasis in morbidly obese individuals at high risk to develop diabetes. Insulin secretion, insulin clearance, and different β-cell function components were estimated by modeling plasma glucose, insulin and C-peptide profiles during 75-g oral glucose tolerance tests (OGTTs) performed at baseline and after 4 weeks of each dietary intervention. The average weight loss was 5%, being 58% greater in the low-carbohydrate-group than Mediterranean-group. Fasting plasma glucose and glucose tolerance were not affected by the diets. The two dietary regimens proved similarly effective in improving insulin resistance and fasting hyperinsulinemia, while enhancing endogenous insulin clearance and β-cell glucose sensitivity. In summary, we demonstrated that a low-carbohydrate diet is a successful short-term approach for weight loss in morbidly obese patients and a feasible alternative to the Mediterranean diet for its glucometabolic benefits, including improvements in insulin resistance, insulin clearance and β-cell function. Further studies are needed to compare the long-term efficacy and safety of the two diets.
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Randomized crossover trial of a modified ketogenic diet in Alzheimer's disease.
Phillips, MCL, Deprez, LM, Mortimer, GMN, Murtagh, DKJ, McCoy, S, Mylchreest, R, Gilbertson, LJ, Clark, KM, Simpson, PV, McManus, EJ, et al
Alzheimer's research & therapy. 2021;13(1):51
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Most people with dementia have Alzheimer’s disease (AD), a disorder that characteristically results in progressive cognitive and functional decline. Brain energy metabolism is impaired in AD. Ketogenic diets can theoretically mitigate impaired brain energy metabolism in AD, leading to improved cognition, daily function, or quality of life. Ketogenic diets are high-fat, low-carbohydrate diets that shift the body towards fat metabolism. The aim of this study was to determine whether a 12-week modified ketogenic diet was well-tolerated and improved cognition, daily function, or quality of life in a hospital clinic of AD patients. This study is a single-phase, assessor-blinded, two-period randomised crossover trial. Participants (n=26) were randomised (1:1 allocation) to a modified ketogenic diet (intervention diet) or their usual diet supplemented with low-fat healthy-eating guidelines and optional recipes (control diet). Results show that high rates of retention and adherence are achievable by following a 12-week modified ketogenic diet to AD patients. Compared with a usual diet supplemented with low-fat healthy-eating guidelines, patients on the ketogenic diet improved in daily function and quality of life. Furthermore, changes in cardiovascular risk factors were mostly favourable and adverse effects were mild. Authors conclude that ketogenic diets may hold promise as viable and effective treatment strategies in AD, but larger and longer studies are needed in order to draw definitive conclusions.
Abstract
BACKGROUND Brain energy metabolism is impaired in Alzheimer's disease (AD), which may be mitigated by a ketogenic diet. We conducted a randomized crossover trial to determine whether a 12-week modified ketogenic diet improved cognition, daily function, or quality of life in a hospital clinic of AD patients. METHODS We randomly assigned patients with clinically confirmed diagnoses of AD to a modified ketogenic diet or usual diet supplemented with low-fat healthy-eating guidelines and enrolled them in a single-phase, assessor-blinded, two-period crossover trial (two 12-week treatment periods, separated by a 10-week washout period). Primary outcomes were mean within-individual changes in the Addenbrookes Cognitive Examination - III (ACE-III) scale, AD Cooperative Study - Activities of Daily Living (ADCS-ADL) inventory, and Quality of Life in AD (QOL-AD) questionnaire over 12 weeks. Secondary outcomes considered changes in cardiovascular risk factors and adverse effects. RESULTS We randomized 26 patients, of whom 21 (81%) completed the ketogenic diet; only one withdrawal was attributed to the ketogenic diet. While on the ketogenic diet, patients achieved sustained physiological ketosis (12-week mean beta-hydroxybutyrate level: 0.95 ± 0.34 mmol/L). Compared with usual diet, patients on the ketogenic diet increased their mean within-individual ADCS-ADL (+ 3.13 ± 5.01 points, P = 0.0067) and QOL-AD (+ 3.37 ± 6.86 points, P = 0.023) scores; the ACE-III also increased, but not significantly (+ 2.12 ± 8.70 points, P = 0.24). Changes in cardiovascular risk factors were mostly favourable, and adverse effects were mild. CONCLUSIONS This is the first randomized trial to investigate the impact of a ketogenic diet in patients with uniform diagnoses of AD. High rates of retention, adherence, and safety appear to be achievable in applying a 12-week modified ketogenic diet to AD patients. Compared with a usual diet supplemented with low-fat healthy-eating guidelines, patients on the ketogenic diet improved in daily function and quality of life, two factors of great importance to people living with dementia. TRIAL REGISTRATION This trial is registered on the Australia New Zealand Clinical Trials Registry, number ACTRN12618001450202 . The trial was registered on August 28, 2018.
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Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial.
Kahleova, H, Petersen, KF, Shulman, GI, Alwarith, J, Rembert, E, Tura, A, Hill, M, Holubkov, R, Barnard, ND
JAMA network open. 2020;3(11):e2025454
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Obesity is uncommon in individuals on a plant-based diet, possibly due to the high-fiber low fat nature of this style of eating and due to the fact that low levels of fat may increase metabolism levels. The aim of this randomised control trial of 244 people following a vegan diet was to assess the effects of a low-fat vegan diet on body weight, insulin resistance (IR), metabolism and lipid levels in the liver and muscle over 16 weeks. The results showed that individuals who followed the low-fat vegan diet as opposed to a normal vegan diet lost more weight, attributed to a loss of body fat and had decreased cholesterol levels. Measures of how the body balances blood sugars were improved and this was directly related to weight loss. The amount of energy needed to digest the food in the intervention diet was increased compared to the control group and this was involved in a relationship whereby as fat mass decreased, blood sugar balance improved, and metabolism increased. Liver lipids decreased in the intervention group, which was directly related to body weight loss and as liver lipids decreased, blood sugar balance increased. Muscle lipids were significantly decreased in the intervention group compared to the control group. It was shown that as fat mass decreased, muscle fat levels and blood sugar balance improved. It was concluded that the low-fat plant-based diet reduced body weight due to a reduced energy intake and increased body metabolism following eating. Blood sugar control was improved due to reduced fat levels in the muscles and liver. This study could be used by healthcare professionals to recommend a low-fat plant based diet to individuals who are overweight and/or who are showing signs of blood sugar imbalance.
Abstract
Importance: Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions. Objective: To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults. Design, Setting, and Participants: This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone. Interventions: Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks. Main Outcomes and Measures: At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis. Results: Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01). Conclusions and Relevance: A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity. Trial Registration: ClinicalTrials.gov Identifier: NCT02939638.
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The Effect of an 8 Week Prescribed Exercise and Low-Carbohydrate Diet on Cardiorespiratory Fitness, Body Composition and Cardiometabolic Risk Factors in Obese Individuals: A Randomised Controlled Trial.
Perissiou, M, Borkoles, E, Kobayashi, K, Polman, R
Nutrients. 2020;12(2)
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Low carbohydrate (CHO) and ketogenic diets have been shown to be effective for weight loss and improving cardiometabolic risk factors. However, they have also been associated with reduced muscle and bone mass, although this may be ameliorated by exercise. The aim of this randomised trial was to assess the effects of an 8-week exercise programme, comprising resistance and aerobic exercise, alongside a low CHO diet on cardiometabolic factors in overweight and obese people. 85 patients were randomised to the 8-week exercise programme (4x45 minute sessions per week) and either a low CHO diet, with a maximum of 50 grams of CHO per day, or standard dietary advice. The participants in the low CHO had greater improvements in cardiorespiratory fitness, blood glucose levels, triglycerides and C-reactive protein (CRP, an inflammatory marker) than the control group. They lost more fat but also more muscle mass than the control group. The improvements seen in the low CHO group were associated with reaching a state of ketosis, an alternative energy state when glucose levels are low. The authors conclude that the longer-term effects of low CHO diets should be explored further.
Abstract
BACKGROUND Low-carbohydrate (LC) diets are an effective method for treating obesity and reducing cardiometabolic risk. However, exposure to LC diets is associated with reductions in muscle mass and increased osteoporosis risk in obese individuals. The combination of exercise with a LC diet appears to attenuate muscle mass loss induced by LC diets alone, and to further improve cardiometabolic profile. However, evidence to date in obese individuals is limited. We assessed the effect of LC diet in combination with supervised exercise on cardiorespiratory fitness, body composition and cardiometabolic risk factors in obese individuals. Methods: Male and female participants in the experimental (EX-LC; structured supervised exercise program + low-carbohydrate meals; n = 33; 35.3 years) and control (EX-CO; structured supervised exercise program + standard dietary advice; n = 31; 34.2 years) conditions underwent measurements of cardiorespiratory fitness (VO2peak), body fat, lean muscle mass (LMM), and cardiometabolic biomarkers before and after an 8 week intervention. Results: Participants in the EX-LC condition demonstrated greater improvements in VO2peak (p = 0.002) and fat mass index (FMI, p = 0.001) compared to the EX-CO condition. Achieving a ketogenic state (β-hydroxybutyrate, βHB ≥0.3 mmol/L) was associated with greater reductions in total body fat (p = 0.011), visceral adipose tissue (p = 0.025), FMI (p = 0.002) and C-reactive protein (CRP, p = 0.041) but also with greater reductions in LMM (p = 0.042). Conclusion: Short-term LC diet combined with prescribed exercise enhanced cardiorespiratory fitness and the cardiometabolic profile of obese individuals but was also associated with greater muscle mass loss compared to similar exercise training and standard dietary advice. The long-term effects of the LC diet should be further explored in future studies.
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Lifestyle factors and visceral adipose tissue: Results from the PREDIMED-PLUS study.
Galmes-Panades, AM, Konieczna, J, Abete, I, Colom, A, Rosique-Esteban, N, Zulet, MA, Vázquez, Z, Estruch, R, Vidal, J, Toledo, E, et al
PloS one. 2019;14(1):e0210726
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Excess visceral adipose tissue (VAT, abdominal fat) is a risk factor for developing cardiovascular disease, type 2 diabetes mellitus and all cause mortality. Lifestyle factors, including diet and physical activity, are associated with VAT. This cross-sectional study evaluated the association between different levels of physical activity (PA), adherence to an energy-restricted Mediterranean diet and sedentary lifestyle with VAT in older people with overweight/obesity and metabolic syndrome. Data were taken from an ongoing randomised study evaluating the effect of a weight loss programme based on an energy-restricted Mediterranean diet, promotion of physical activity and behavioural support compared to usual care consisting of advice on an energy-unrestricted Mediterranean diet only. Total and moderate-to-vigorous physical activity and muscle strength were inversely, and sedentary behaviour was positively associated with VAT. There was no statistically significant association between VAT and light exercise, adherence to the energy-reduced Mediterranean diet and watching TV.
Abstract
BACKGROUND Visceral adipose tissue (VAT) is a strong predictor of cardiometabolic health, and lifestyle factors may have a positive influence on VAT depot. This study aimed to assess the cross-sectional associations between baseline levels of physical activity (PA), sedentary behaviours (SB) and adherence to the Mediterranean diet (MedDiet) with VAT depot in older individuals with overweight/obesity and metabolic syndrome. METHODS Baseline data of the PREDIMED-Plus study including a sample of 1,231 Caucasian men and women aged 55-75 years were used. Levels of leisure-time PA (total, light, and moderate-to-vigorous, in METs·min/day) and SB (total and TV-viewing, in h/day) were evaluated using validated questionnaires. Adherence to the MedDiet was evaluated using a 17-item energy-restricted MedDiet (erMedDiet) screener. The chair-stand test was used to estimate the muscle strength. VAT depot was assessed with DXA-CoreScan. Multivariable adjusted linear regression models were used to evaluate the association between lifestyle factors and VAT. For the statistics we had used multiadjusted linear regression models. RESULTS Total leisure-time PA (100 METs·min/day: β -24.3g, -36.7;-11.9g), moderate-to-vigorous PA (β -27.8g, 95% CI -40.8;-14.8g), chair-stand test (repeat: β -11.5g, 95% CI -20.1;-2.93g) were inversely associated, and total SB (h/day: β 38.2g, 95% CI 14.7;61.7) positively associated with VAT. Light PA, TV-viewing time and adherence to an erMedDiet were not significantly associated with VAT. CONCLUSIONS In older adults with overweigh/obesity and metabolic syndrome, greater PA, muscle strength, and lower total SB were associated with less VAT depot. In this study, adherence to an erMedDiet was not associated with lower VAT.
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Effect of a Low Free Sugar Diet vs Usual Diet on Nonalcoholic Fatty Liver Disease in Adolescent Boys: A Randomized Clinical Trial.
Schwimmer, JB, Ugalde-Nicalo, P, Welsh, JA, Angeles, JE, Cordero, M, Harlow, KE, Alazraki, A, Durelle, J, Knight-Scott, J, Newton, KP, et al
JAMA. 2019;321(3):256-265
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The prevalence of non-alcoholic fatty liver disease (NAFLD) among children in the United States is increasing and evidence supports a role for dietary sugar in the development and progression of NAFLD. This open-label, randomised clinical trial using a feeding study design was performed to test the hypothesis that restricting free sugar would improve NAFLD in children. Children in the intervention group, who were provided all food for the 8 week intervention, received less than 3% of daily calories from sugar. The control group continued with their usual diet. Study visits were conducted at baseline and at 4 and 8 weeks after start of the intervention. The mean decrease in hepatic steatosis (a sign of NAFLD) from baseline to week 8 was significantly greater for the intervention diet group compared with the usual diet group. Liver enzymes, total cholesterol, weight/body mass index and systolic blood pressure also improved more in the low sugar group than in the usual diet group. There was no difference in markers for blood sugar control and other lipid parameters. The authors conclude that these findings suggest a potential benefit of a low sugar diet for children with NAFLD, but state that further research is needed to assess long-term and clinical outcomes.
Abstract
Importance: Pediatric guidelines for the management of nonalcoholic fatty liver disease (NAFLD) recommend a healthy diet as treatment. Reduction of sugary foods and beverages is a plausible but unproven treatment. Objective: To determine the effects of a diet low in free sugars (those sugars added to foods and beverages and occurring naturally in fruit juices) in adolescent boys with NAFLD. Design, Setting, and Participants: An open-label, 8-week randomized clinical trial of adolescent boys aged 11 to 16 years with histologically diagnosed NAFLD and evidence of active disease (hepatic steatosis >10% and alanine aminotransferase level ≥45 U/L) randomized 1:1 to an intervention diet group or usual diet group at 2 US academic clinical research centers from August 2015 to July 2017; final date of follow-up was September 2017. Interventions: The intervention diet consisted of individualized menu planning and provision of study meals for the entire household to restrict free sugar intake to less than 3% of daily calories for 8 weeks. Twice-weekly telephone calls assessed diet adherence. Usual diet participants consumed their regular diet. Main Outcomes and Measures: The primary outcome was change in hepatic steatosis estimated by magnetic resonance imaging proton density fat fraction measurement between baseline and 8 weeks. The minimal clinically important difference was assumed to be 4%. There were 12 secondary outcomes, including change in alanine aminotransferase level and diet adherence. Results: Forty adolescent boys were randomly assigned to either the intervention diet group or the usual diet group (20 per group; mean [SD] age, 13.0 [1.9] years; most were Hispanic [95%]) and all completed the trial. The mean decrease in hepatic steatosis from baseline to week 8 was significantly greater for the intervention diet group (25% to 17%) vs the usual diet group (21% to 20%) and the adjusted week 8 mean difference was -6.23% (95% CI, -9.45% to -3.02%; P < .001). Of the 12 prespecified secondary outcomes, 7 were null and 5 were statistically significant including alanine aminotransferase level and diet adherence. The geometric mean decrease in alanine aminotransferase level from baseline to 8 weeks was significantly greater for the intervention diet group (103 U/L to 61 U/L) vs the usual diet group (82 U/L to 75 U/L) and the adjusted ratio of the geometric means at week 8 was 0.65 U/L (95% CI, 0.53 to 0.81 U/L; P < .001). Adherence to the diet was high in the intervention diet group (18 of 20 reported intake of <3% of calories from free sugar during the intervention). There were no adverse events related to participation in the study. Conclusions and Relevance: In this study of adolescent boys with NAFLD, 8 weeks of provision of a diet low in free sugar content compared with usual diet resulted in significant improvement in hepatic steatosis. However, these findings should be considered preliminary and further research is required to assess long-term and clinical outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT02513121.
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Effects of Dietary Protein and Fat Content on Intrahepatocellular and Intramyocellular Lipids during a 6-Day Hypercaloric, High Sucrose Diet: A Randomized Controlled Trial in Normal Weight Healthy Subjects.
Surowska, A, Jegatheesan, P, Campos, V, Marques, AS, Egli, L, Cros, J, Rosset, R, Lecoultre, V, Kreis, R, Boesch, C, et al
Nutrients. 2019;11(1)
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High sugar diets can lead to increased fat accumulation in the liver and skeletal muscles, as intrahepatocellular lipid (IHCL) and intramyocellular lipid (IMCL) respectively. Elevation in these lipid concentrations is associated with an increased risk of various chronic diseases. The aim of this randomised crossover trial was to assess whether the consequences of a high sugar diet differed according to the protein and fat composition in 12 healthy adults. At the beginning of each trial period, participants consumed a 3-day weight maintenance diet followed by a 6-day high calorie, high sugar diet consisting of either low protein-high fat or high protein-low fat with a 4-8 week washout period. IHCL and IMCL concentrations, energy expenditure and blood metabolites were monitored after each weight maintenance diet and after each 6-day intervention diet period. This study found that both diets led to increased lipid concentrations, most notably the in liver cells. Lipid increases induced by the high protein-low fat diet were significantly lower than those induced by the low protein-high fat diet. Based on these results, the authors conclude that when overfed on a high sugar diet, high protein-low fat markedly reduces the amount of fat accumulation in liver and muscle cells and suggest that either dietary protein may have a protective effect of sugar and fat may have an additive adverse effect.
Abstract
Sucrose overfeeding increases intrahepatocellular (IHCL) and intramyocellular (IMCL) lipid concentrations in healthy subjects. We hypothesized that these effects would be modulated by diet protein/fat content. Twelve healthy men and women were studied on two occasions in a randomized, cross-over trial. On each occasion, they received a 3-day 12% protein weight maintenance diet (WM) followed by a 6-day hypercaloric high sucrose diet (150% energy requirements). On one occasion the hypercaloric diet contained 5% protein and 25% fat (low protein-high fat, LP-HF), on the other occasion it contained 20% protein and 10% fat (high protein-low fat, HP-LF). IHCL and IMCL concentrations (magnetic resonance spectroscopy) and energy expenditure (indirect calorimetry) were measured after WM, and again after HP-LF/LP-HF. IHCL increased from 25.0 ± 3.6 after WM to 147.1 ± 26.9 mmol/kg wet weight (ww) after LP-HF and from 30.3 ± 7.7 to 57.8 ± 14.8 after HP-LF (two-way ANOVA with interaction: p < 0.001 overfeeding x protein/fat content). IMCL increased from 7.1 ± 0.6 to 8.8 ± 0.7 mmol/kg ww after LP-HF and from 6.2 ± 0.6 to 6.9 ± 0.6 after HP-LF, (p < 0.002). These results indicate that liver and muscle fat deposition is enhanced when sucrose overfeeding is associated with a low protein, high fat diet compared to a high protein, low fat diet.
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Role of Calcium and Low-Fat Dairy Foods in Weight-Loss Outcomes Revisited: Results from the Randomized Trial of Effects on Bone and Body Composition in Overweight/Obese Postmenopausal Women.
Ilich, JZ, Kelly, OJ, Liu, PY, Shin, H, Kim, Y, Chi, Y, Wickrama, KKAS, Colic-Baric, I
Nutrients. 2019;11(5)
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A woman’s menopausal years are believed to bring about weight gain due to various biological mechanisms, such as depletion of oestrogen. Many women undertake weight loss diets, in an attempt to control the weight gain, and although weight loss can reduce the risk factors for metabolic and cardiovascular disease etc, it can also lead to accelerated loss bone density and muscle mass. The objective of this study was to investigate whether by complementing a low-calorie diet with 4 to 5 servings of low-fat dairy foods per day and/or supplementing with calcium and vitamin D supplements would aid weight loss and preserve either/both bone and muscle mass. The study was conducted on 189 early postmenopausal, obese women. It was a randomized, placebo-controlled clinical trial conducted over 6 months. Researchers found that results were better for the participants on the low-fat dairy foods and those supplementing with calcium and vitamin D when compared to the placebo group (who only had placebo pills). They suggest that when embarking on a weight loss program it is beneficial to include 4 to 5 servings of low-fat dairy foods each day and take calcium and vitamin D supplements will have a positive impact on weight loss, bone density and muscle mass in post-menopausal women.
Abstract
Several studies have investigated the possibility of dairy foods and calcium (Ca) mediating weight and body composition, but a consensus has not been reached. We aimed to investigate weight-loss-related outcomes during intervention with low-fat dairy foods or Ca + vitamin D supplements, both as complements to hypocaloric diets. Overweight/obese Caucasian, early-postmenopausal women (n = 135) were recruited for a 6 month energy-restricted weight loss study complemented with either low-fat dairy foods (D; 4-5 servings/day), or Ca + vitamin D supplements (S); both to amount a total of ~1500 mg/day and 600 IU/day of Ca and vitamin D, respectively, or placebo pills (C). Bone mineral density (BMD) and lean and fat tissue were measured by Lunar iDXA. Serum and urinary markers of bone turnover were analyzed. Diet and physical activity were assessed with 3-day records. Participants on average lost ~4%, ~3%, and ~2% of body weight, fat, and lean tissue, respectively. The significantly better outcomes were noticed in participants in the D group regarding body composition (fat loss/lean tissue preservation) and in participants in the S group regarding the BMD outcomes, compared to those in the C group. Therefore, increasing low-fat dairy foods to 4-5 servings/day and/or increasing Ca & vitamin D intake by supplements (in those who are at the borderline dietary intake) may be beneficial for weight loss/maintenance and may lead to more favorable bone and body composition outcomes in postmenopausal women during moderate weight loss.
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Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study.
Panizza, CE, Lim, U, Yonemori, KM, Cassel, KD, Wilkens, LR, Harvie, MN, Maskarinec, G, Delp, EJ, Lampe, JW, Shepherd, JA, et al
Nutrients. 2019;11(6)
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Excess adiposity is known to contribute to many metabolic diseases. Intermittent energy restriction (IER) has emerged as a favourable method of calorie reduction, and combining IER with the Mediterranean diet has shown promising results for reducing body fat and improving insulin resistance. The aim of this pilot study was to explore efficacy of an IER and Mediterranean diet in adiposity reduction in 60 Japanese Americans. Participants were randomised to either consume the IER + Mediterranean diet (22) or a control anti-hypertension diet (26) for 12 weeks. At baseline and 12-weeks, visceral adipose tissue and total fat mass were measured. Phone check-ins were completed weekly for the 12-weeks and both groups had equivalent dietetic support. This study found significant reductions in total fat mass in the IER + Mediterranean group compared with the control group, and found diet adherence to be high. Based on these results, the authors conclude the IER and Mediterranean diet combined can lower total adiposity and potentially improve liver function among Japanese Americans.
Abstract
Intermittent energy restriction combined with a Mediterranean diet (IER+MED) has shown promise to reduce body fat and insulin resistance. In the Multiethnic Cohort Adiposity Phenotype Study, Japanese Americans had the highest visceral adipose tissue (VAT) when adjusting for total adiposity. We conducted this pilot study to demonstrate feasibility and explore efficacy of following IER+MED for 12 weeks to reduce VAT among East Asians in Hawaii. Sixty volunteers (aged 35-55, BMI 25-40 kg/m2, VAT ≥ 90 cm2 for men and ≥ 80 cm2 for women) were randomized to IER+MED (two consecutive days with 70% energy restriction and 5 days euenergetic MED) or an active comparator (euenergetic Dietary Approaches to Stop Hypertension (DASH) diet). Participants and clinic staff (except dietitians) were blinded to group assignments. IER+MED had significantly larger reductions in DXA-measured VAT and total fat mass (-22.6 ± 3.6 cm2 and -3.3 ± 0.4 kg, respectively) vs. DASH (-10.7 ± 3.5 cm2 and -1.6 ± 0.4 kg) (p = 0.02 and p = 0.005). However, after adjusting for total fat mass, change in VAT was not statistically different between groups; whereas, improvement in alanine transaminase remained significantly greater for IER+MED vs. DASH (-16.2 ± 3.8 U/L vs. -4.0 ± 3.6 U/L, respectively, p = 0.02). Attrition rate was 10%, and participants adhered well to study prescriptions with no reported major adverse effect. Results demonstrate IER+MED is acceptable, lowers visceral and total adiposity among East Asian Americans, and may improve liver function more effectively than a healthful diet pattern. ClinicalTrials.gov Identifier: NCT03639350.
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Effects of 3-week total meal replacement vs. typical food-based diet on human brain functional magnetic resonance imaging food-cue reactivity and functional connectivity in people with obesity.
Kahathuduwa, CN, Davis, T, O'Boyle, M, Boyd, LA, Chin, SH, Paniukov, D, Binks, M
Appetite. 2018;120:431-441
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Weight loss diets that use total meal replacement shakes have been shown to reduce food cravings compared to typical reduced-calorie diets. The mechanism for this is unclear. This study examined the effects of a 3-week 1120 kcal per day meal replacement diet compared to a reduced calorie diet on activity in areas of the brain associated with food cravings. Thirty-two obese adults participated in the study. Before and after the study, the participants were given magnetic resonance imaging (MRI) scans to measure activity in different areas of the brain. They were also questioned on food cravings and weighed. The group following the meal replacement diet experienced a significant weight loss of 4.87 kg, a reduction in body fat of 2.19 kg and reduced their overall food cravings. The reduced calorie diet group also experienced significant weight loss and a reduction in body fat (2.37kg and 1.64kg, respectively) but less than the meal replacement group. The meal replacement group experienced reduced cravings compared to the reduced calorie diet group. MRI scans suggested that this was due to changes in activity in the food reward related regions in several areas of the brain, resulting in an increase in executive control. The authors concluded that meal replacement diets may increase executive control within the brain, leading to a reduction in food cravings and weight loss.
Abstract
OBJECTIVES Calorie restriction via total meal replacement (TMR) results in greater reduction of food cravings compared to reduced-calorie typical diet (TD). Direct evidence of the impact of these interventions on human brain fMRI food-cue reactivity (fMRI-FCR) and functional connectivity is absent. We examined the effects of a 3-week 1120 kcal/d TMR intervention as compared to an iso-caloric TD intervention using an fMRI-FCR paradigm. METHODS Thirty-two male and female subjects with obesity (19-60 years; 30-39.9 kg/m2) participated in a randomized two-group repeated measures dietary intervention study consisting of 1120 kcal/d from either 1) TMR (shakes), 2) TD (portion control). Pre-intervention and following the 3-week diet fMRI-FCR, functional connectivity, food cravings (Food Craving Inventory) and weight were considered. RESULTS Compared to TD, TMR showed increased fMRI-FCR of the bilateral dorsolateral prefrontal (dlPFC), orbitofrontal, anterior cingulate, primary motor and left insular cortices and bilateral nucleus accumbens regions in the post-intervention state relative to the pre-intervention state. Compared to TD, TMR was also associated with negative modulation of fMRI-FCR of the nucleus accumbens, orbitofrontal cortex and amygdala by dlPFC. Reduced body weight (4.87 kg, P < 0.001), body fat (2.19 kg, P = 0.004) and overall food cravings (0.41, P = 0.047) were seen in the TMR group. In the TD group reduced body weight (2.37 kg, P = 0.004) and body fat (1.64 kg, P = 0.002) were noted. Weight loss was significantly greater in TMR versus TD (2.50 kg, P = 0.007). CONCLUSIONS Greater weight loss and reduced cravings, coupled with stronger activations and potential negative modulation of the food reward related regions by the dlPFC during exposure to visual food cues is consistent with increased executive control in TMR vs. TD.