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Effects of Intermittent Energy Restriction Compared with Those of Continuous Energy Restriction on Body Composition and Cardiometabolic Risk Markers - A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults.
Schroor, MM, Joris, PJ, Plat, J, Mensink, RP
Advances in nutrition (Bethesda, Md.). 2024;15(1):100130
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Intermittent energy restriction (IER) diets, such as the 5:2 diet, time-restricted eating (TRE), and alternate-day fasting (ADF), are gaining popularity. According to previous research, IER protocols effectively manage obesity and may have many other health benefits, including improving metabolic health. This systematic review and meta-analysis of twenty-eight parallel-design randomised controlled trials looked at the benefits of IER protocols, such as ADF, TRE, and the 5:2 diet, and the effects of continuous energy restriction (CER) on anthropometric and cardiometabolic outcomes. The results of this systematic review and meta-analysis showed that both the IER and CER are equally beneficial. However, IER protocols showed greater but clinically insignificant improvements in fat-free mass and waist circumference in healthy adults. IER and CER protocols were not different in improving the lipid profile, glucose and insulin levels and blood pressure. Different IER diets showed different positive effects on metabolic parameters. Future robust studies are required to assess the effects of these energy-restriction diets on metabolic and anthropometric parameters because of the high variability in the included studies. However, healthcare professionals can use the results of this review to understand the potential clinical utility of various energy-restriction diets.
Abstract
The interest in intermittent energy restriction (IER) diets as a weight-loss approach is increasing. Different IER protocols exist, including time-restricted eating (TRE), alternate-day fasting (ADF), and the 5:2 diet. This meta-analysis compared the effects of these IER diets with continuous energy restriction (CER) on anthropometrics and cardiometabolic risk markers in healthy adults. Twenty-eight trials were identified that studied TRE (k = 7), ADF (k = 10), or the 5:2 diet (k = 11) for 2-52 wk. Energy intakes between intervention groups within a study were comparable (17 trials), lower in IER (5 trials), or not reported (6 trials). Weighted mean differences (WMDs) were calculated using fixed- or random-effects models. Changes in body weight [WMD: -0.42 kg; 95% confidence interval (CI): -0.96 to 0.13; P = 0.132] and fat mass (FM) (WMD: -0.31 kg; 95% CI: -0.98 to 0.36; P = 0.362) were comparable when results of the 3 IER diets were combined and compared with those of CER. All IER diets combined reduced fat-free mass (WMD: -0.20 kg; 95% CI: -0.39 to -0.01; P = 0.044) and waist circumference (WMD: -0.91 cm; 95% CI: -1.76 to -0.06; P = 0.036) more than CER. Effects on body mass index [BMI (kg/m2)], glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), serum lipid and lipoprotein concentrations, and blood pressure did not differ. Further, TRE reduced body weight, FM, and fat-free mass more than CER, whereas ADF improved HOMA-IR more. BMI was reduced less in the 5:2 diet compared with CER. In conclusion, the 3 IER diets combined did not lead to superior improvements in anthropometrics and cardiometabolic risk markers compared with CER diets. Slightly greater reductions were, however, observed in fat-free mass and waist circumference. To what extent differences in energy intakes between groups within studies may have influenced these outcomes should be addressed in future studies.
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Dietary carbohydrate restriction augments weight loss-induced improvements in glycaemic control and liver fat in individuals with type 2 diabetes: a randomised controlled trial.
Thomsen, MN, Skytte, MJ, Samkani, A, Carl, MH, Weber, P, Astrup, A, Chabanova, E, Fenger, M, Frystyk, J, Hartmann, B, et al
Diabetologia. 2022;65(3):506-517
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The carbohydrate restricted diet has been shown to be beneficial for Type 2 diabetes (T2D) management and reducing cardiovascular disease risk. This open-label, parallel randomised controlled trial involved Type 2 diabetic patients taking antidiabetic medications who restricted their energy intake by following either a carbohydrate-reduced high protein diet or a conventional diabetic diet. Participants in both groups had a 5.9% reduction in body weight, similar changes in fasting NEFA, apoB, apoA-1, total cholesterol, LDL-cholesterol, HDL-cholesterol, and non-HDL cholesterol, and a significant reduction in fasting glucose, insulin, C-peptide, and HOMA2-IR after 6 weeks of intervention. Carbohydrate-reduced high protein diet group showed a greater reduction in HbA1c and diurnal mean glucose, glycaemic variability, fasting triacylglycerol concentration and liver fat content. Carbohydrate-reduced high protein diet caused an adverse reaction in some patients, and those following a carbohydrate-reduced high protein diet excreted more urea than those eating a conventional diabetic diet. To confirm the results of this study, long-term robust studies are needed. This study can assist healthcare professionals in understanding the benefits of following a carbohydrate-reduced high protein diet in improving glycaemic control, triglyceride levels, and reducing body weight in Type 2 diabetes patients.
Abstract
AIMS/HYPOTHESIS Lifestyle modification and weight loss are cornerstones of type 2 diabetes management. However, carbohydrate restriction may have weight-independent beneficial effects on glycaemic control. This has been difficult to demonstrate because low-carbohydrate diets readily decrease body weight. We hypothesised that carbohydrate restriction enhances the beneficial metabolic effects of weight loss in type 2 diabetes. METHODS This open-label, parallel RCT included adults with type 2 diabetes, HbA1c 48-97 mmol/mol (6.5-11%), BMI >25 kg/m2, eGFR >30 ml min-1 [1.73 m]-2 and glucose-lowering therapy restricted to metformin or dipeptidyl peptidase-4 inhibitors. Participants were randomised by a third party and assigned to 6 weeks of energy restriction (all foods were provided) aiming at ~6% weight loss with either a carbohydrate-reduced high-protein diet (CRHP, percentage of total energy intake [E%]: CH30/P30/F40) or a conventional diabetes diet (CD, E%: CH50/P17/F33). Fasting blood samples, continuous glucose monitoring and magnetic resonance spectroscopy were used to assess glycaemic control, lipid metabolism and intrahepatic fat. Change in HbA1c was the primary outcome; changes in circulating and intrahepatic triacylglycerol were secondary outcomes. Data were collected at Copenhagen University Hospital (Bispebjerg and Herlev). RESULTS Seventy-two adults (CD 36, CRHP 36, all white, 38 male sex) with type 2 diabetes (mean duration 8 years, mean HbA1c 57 mmol/mol [7.4%]) and mean BMI of 33 kg/m2 were enrolled, of which 67 (CD 33, CRHP 34) completed the study. Body weight decreased by 5.8 kg (5.9%) in both groups after 6 weeks. Compared with the CD diet, the CRHP diet further reduced HbA1c (mean [95% CI] -1.9 [-3.5, -0.3] mmol/mol [-0.18 (-0.32, -0.03)%], p = 0.018) and diurnal mean glucose (mean [95% CI] -0.8 [-1.2, -0.4] mmol/l, p < 0.001), stabilised glucose excursions by reducing glucose CV (mean [95% CI] -4.1 [-5.9, -2.2]%, p < 0.001), and augmented the reductions in fasting triacylglycerol concentration (by mean [95% CI] -18 [-29, -6]%, p < 0.01) and liver fat content (by mean [95% CI] -26 [-45, 0]%, p = 0.051). However, pancreatic fat content was decreased to a lesser extent by the CRHP than the CD diet (mean [95% CI] 33 [7, 65]%, p = 0.010). Fasting glucose, insulin, HOMA2-IR and cholesterol concentrations (total, LDL and HDL) were reduced significantly and similarly by both diets. CONCLUSIONS/INTERPRETATION Moderate carbohydrate restriction for 6 weeks modestly improved glycaemic control, and decreased circulating and intrahepatic triacylglycerol levels beyond the effects of weight loss itself compared with a CD diet in individuals with type 2 diabetes. Concurrent differences in protein and fat intakes, and the quality of dietary macronutrients, may have contributed to these results and should be explored in future studies. TRIAL REGISTRATION ClinicalTrials.gov NCT03814694. FUNDING The study was funded by Arla Foods amba, The Danish Dairy Research Foundation, and Copenhagen University Hospital Bispebjerg Frederiksberg.
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Effects of intermittent very-low calorie diet on glycemic control and cardiovascular risk factors in obese patients with type 2 diabetes mellitus: A randomized controlled trial.
Umphonsathien, M, Rattanasian, P, Lokattachariya, S, Suansawang, W, Boonyasuppayakorn, K, Khovidhunkit, W
Journal of diabetes investigation. 2022;13(1):156-166
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Various studies have shown that intermittent low-calorie diets are effective in reducing weight and improving glycaemic control. In this randomized controlled trial, two intermittent very-low calorie diets (2 days per week and 4 days per week) were evaluated against a control group with respect to achieving diabetes remission, improving glycemic control, metabolic parameters, and quality of life in Type 2 diabetic patients. There was a significant reduction in HbA1c and insulin resistance in the 2 days/week and 4 days/week intermittent very-low calorie groups at week 20. Both the intervention groups achieved diabetes remission with 29% of participants not requiring glucose-lowering medications at week 20. Both intervention groups also showed a significant reduction in serum triglycerides, body weight, body mass index, and fat mass. Aspartate transaminase and alanine aminotransferase levels, as well as blood pressure, decreased significantly with a 4 day/week intermittent low-calorie diet. Both intervention groups experienced improved quality of life at week 10 and the interventions were generally well tolerated. To generalise the results, longer-term, robust studies are required. These results can help healthcare providers understand the clinical relevance of intermittent very-low calorie diets in managing Type 2 diabetes and obesity.
Abstract
AIMS/INTRODUCTION Very few studies assess the effectiveness of different protocols of intermittent very-low calorie diet (VLCD) in patients with diabetes. This study was designed to compare the effects of 2 days/week and 4 days/week of intermittent VLCD on glycemic control, diabetes remission, metabolic parameters and quality of life in patients with type 2 diabetes and obesity. MATERIALS AND METHODS Participants with obesity and type 2 diabetes were recruited and randomly assigned to three groups, consisting of control, 2 days/week and 4 days/week of intermittent VLCD. In the intermittent VLCD groups, participants received a 600-kcal diet per day on restricted days and ad libitum food consumption on non-restricted days. Glycemic control, rate of diabetes remission, metabolic parameters and quality of life were evaluated at baseline, weeks 2, 10 and 20. RESULTS A total of 40 participants were enrolled. The mean body mass index was 30.1 ± 5.9 kg/m2 , and the mean glycated hemoglobin was 7.4 ± 1.2%. At week 20, there was an improvement in glycemic control in both intermittent VLCD groups with significant decreases in glycated hemoglobin levels and insulin resistance index throughout the study periods. Diabetes remission without the need for medications was equally found in 29% of participants in both intermittent VLCD groups. Serum triglyceride, bodyweight, body mass index and fat mass were also significantly decreased in both VLCD groups. No serious adverse events were encountered. CONCLUSION Intermittent VLCD was highly effective in achieving optimal glycemic control. The effects of 2 days/week and 4 days/week of intermittent VLCD on diabetes remission were relatively similar.
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The effect of periodic ketogenic diet on newly diagnosed overweight or obese patients with type 2 diabetes.
Li, S, Lin, G, Chen, J, Chen, Z, Xu, F, Zhu, F, Zhang, J, Yuan, S
BMC endocrine disorders. 2022;22(1):34
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Currently, the ketogenic diet is gaining popularity in managing Type 2 diabetes (T2D). Ketogenic diets replace carbohydrates with fat and include limited carbohydrates and adequate protein. This randomised controlled trial evaluated the effects of the 12-week ketogenic diet on sixty overweight or obese T2D patients. Both the ketogenic and control diabetes diet groups achieved significant reductions in weight, body mass index, waist circumference, triglycerides, total cholesterol, low-density lipoprotein, high-density lipoprotein, fasting blood glucose, fasting insulin, and HbA1c. However, the ketogenic group showed significantly greater reductions in body mass, blood lipids, and blood glucose than the control group. In the ketogenic diet group, serum uric acid levels were higher than those in the control diet group. It was found that the control diet group adhered to the diet for a longer period than the ketogenic diet group, whose willingness to adhere to the diet long-term was weaker. More robust long-term studies are needed to evaluate the long-term effects of a ketogenic diet. In this study, more patients who followed the ketogenic diet experienced hypoglycaemic events during the first four weeks. Healthcare providers should exercise caution when recommending a short term therapeutic ketogenic diet.
Abstract
BACKGROUND The ketogenic diet (KD) is characterized by fat as a substitute of carbohydrates for the primary energy source. There is a large number of overweight or obese people with type 2 diabetes mellitus (T2DM), while this study aims to observe periodic ketogenic diet for effect on overweight or obese patients newly diagnosed as T2DM. METHODS A total of 60 overweight or obese patients newly diagnosed as T2DM were randomized into two groups: KD group, which was given ketogenic diet, and control group, which was given routine diet for diabetes, 30 cases in each group. Both dietary patterns lasted 12 weeks, and during the period, the blood glucose, blood lipid, body weight, insulin, and uric acid before and after intervention, as well as the significance for relevant changes, were observed. RESULTS For both groups, the weight, BMI(body mass index), Waist, TG (triglyceride), TC(cholesterol), LDL (low-density lipoprotein cholesterol), HDL (high-density lipoprotein cholesterol), FBG (fasting glucose), FINS (fasting insulin), HbA1c (glycosylated hemoglobin) were decreased after intervention (P < 0.05), while the decrease rates in the KD group was more significant than the control group. However, UA(serum uric acid) in the KD group showed an upward trend, while in the control group was not changed significantly (P > 0.05).The willingness to adhere to the ketogenic diet over the long term was weaker than to the routine diet for diabetes. CONCLUSION Among the overweight or obese patients newly diagnosed as type 2 diabetes mellitus, periodic ketogenic diet can not only control the body weight, but also control blood glucose and lipid, but long-term persistence is difficult.
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The potential prolonged effect at one-year follow-up after 18-month randomized controlled trial of a 90 g/day low-carbohydrate diet in patients with type 2 diabetes.
Chen, CY, Huang, WS, Ho, MH, Chang, CH, Lee, LT, Chen, HS, Kang, YD, Chie, WC, Jan, CF, Wang, WD, et al
Nutrition & diabetes. 2022;12(1):17
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A low carbohydrate diet (LCD) could be an effective dietary strategy for managing Type 2 Diabetes and body weight. This follow-up of a randomised controlled study evaluated the effect of moderate LCD after 18 months of 90 g/day LCD in 85 poorly controlled Type 2 Diabetic patients and compared it with Traditional Diabetic Diet (TDD). Those who followed the LCD diet ate significantly fewer carbohydrates and more protein and fat at the follow up between 18 and 30 months compared to those who followed the TDD group. The LCD group also showed significant improvements in serum HbA1C, two-hour serum glucose, serum alanine aminotransferase and Medication Effect Score in comparison with the TDD group. However, the level of triglycerides increased, and HDL levels decreased significantly in the LCD group from 18 to 30 months. There was however no significant difference between the groups in the improvement of HbA1C, fasting serum glucose, 2 h serum glucose, as well as serum cholesterol, triglycerides, low-density lipoprotein, ALT, creatinine, and urine microalbumin. To confirm the benefits of LCD on glycaemic control, further robust studies are needed. Results of this study can help healthcare professionals gain a better understanding of the prolonged effects of LCD on glycaemic control, liver function, and medication effect scores.
Abstract
OBJECTIVES To evaluate the effect at a one-year follow-up after an 18-month randomized controlled trial (RCT) of 90 gm/day low-carbohydrate diet (LCD) in type 2 diabetes. RESEARCH DESIGN AND METHODS Eighty-five poorly controlled type 2 diabetic patients with an initial HbA1c ≥ 7.5% who have completed an 18-month randomized controlled trial (RCT) on 90 g/day low-carbohydrate diet (LCD) were recruited and followed for one year. A three-day weighted food record, relevant laboratory tests, and medication effect score (MES) were obtained at the end of the previous trial and one year after for a total of 30 months period on specific diet. RESULTS 71 (83.5%) patients completed the study, 35 were in TDD group and 36 were in LCD group. Although the mean of percentage changes in daily carbohydrate intake was significantly lower for those in TDD group than those in LCD group (30.51 ± 11.06% vs. 55.16 ± 21.79%, p = 0.0455) in the period between 18 months and 30 months, patients in LCD group consumed significantly less amount of daily carbohydrate than patients in TDD group (131.8 ± 53.9 g vs. 195.1 ± 50.2 g, p < 0.001). The serum HbA1C, two-hour serum glucose, serum alanine aminotransferase (ALT), and MES were also significantly lower for the LCD group patients than those in the TDD group (p = 0.017, p < 0.001, p = 0.017, and p = 0.008 respectively). The mean of percentage changes of HbA1C, fasting serum glucose, 2 h serum glucose, as well as serum cholesterol, triglyceride, low-density lipoprotein, ALT, creatinine, and urine microalbumin, however, were not significantly different between the two groups (p > 0.05). CONCLUSIONS The one-year follow-up for patients on 90 g/d LCD showed potential prolonged and better outcome on glycaemic control, liver function and MES than those on TDD for poorly controlled diabetic patients.
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Could the ketogenic diet induce a shift in thyroid function and support a metabolic advantage in healthy participants? A pilot randomized-controlled-crossover trial.
Iacovides, S, Maloney, SK, Bhana, S, Angamia, Z, Meiring, RM
PloS one. 2022;17(6):e0269440
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The ketogenic diet (KD) has been shown in several studies to result in weight loss compared to a conventional high-carbohydrate, low-fat diet (HCLF). It is thought that this sort of diet may inhibit the appetite and increase feelings of being fuller for longer. However, its effects on other biological functions which can lead to weight loss are unclear. This randomised control trial of 11 individuals aimed to determine the effect of the KD on thyroid function, which controls the conversion of calories into energy and therefore has a role in fat storage. The results showed that KD resulted in a higher loss of body mass than the HCLF diet and one of the thyroid hormones (T3) was decreased. However, hormones which stimulate thyroid function remained unchanged. It was concluded that changes in metabolism can occur following the KD, which may contribute to a greater loss of weight compared to a HCLF diet. This study could be used by healthcare professionals to understand that the ketogenic diet may be more effective at weight loss than a standard HCLF diet. However larger scale trials are warranted.
Abstract
BACKGROUND The ketogenic diet (KD) has been shown to result in body mass loss in people with disease as well as healthy people, yet the effect of the KD on thyroid function and metabolism are unknown. OBJECTIVE We aimed to determine the effects of a KD, compared with an isocaloric high-carbohydrate low-fat (HCLF) diet, on resting metabolic rate and thyroid function in healthy individuals. DESIGN Eleven healthy, normal-weight participants (mean(SD) age: 30(9) years) completed this randomized crossover-controlled study. For a minimum of three weeks on each, participants followed two isocaloric diets: a HCLF diet (55%carbohydrate, 20%fat, 25%protein) and a KD (15%carbohydrate, 60%fat, 25% protein), with a one-week washout period in-between. Importantly, while on the KD, the participants were required to remain in a state of nutritional ketosis for three consecutive weeks. Crossover analyses and linear mixed models were used to assess effect of diet on body mass, thyroid function and resting metabolic rate. RESULTS Both dietary interventions resulted in significant body mass loss (p<0.05) however three weeks of sustained ketosis (KD) resulted in a greater loss of body mass (mean (95%CI): -2.9 (-3.5, -2.4) kg) than did three weeks on the HCLF diet (-0.4 (-1.0, 0.1) kg, p < 0.0001). Compared to pre-diet levels, the change in plasma T3 concentration was significantly different between the two diets (p = 0.003), such that plasma T3 concentration was significantly lower following the KD diet (4.1 (3.8, 4.4) pmol/L, p<0.0001) but not different following the HCLF diet (4.8 (4.5, 5.2) pmol/L, p = 0.171. There was a significant increase in T4 concentration from pre-diet levels following the KD diet (19.3 (17.8, 20.9) pmol/L, p < 0.0001), but not following the HCLF diet (17.3 (15.7, 18.8) pmol.L, p = 0.28). The magnitude of change in plasma T4 concentration was not different between the two diets (p = 0.4). There was no effect of diet on plasma thyroid stimulating hormone concentration (p = 0.27). There was a significantly greater T3:T4 ratio following the HCLF diet (0.41 (0.27, 0.55), p < 0.0001) compared to pre-diet levels but not following the KD diet (0.25 (0.12, 0.39), p = 0.80). CONCLUSIONS Although the diets were isocaloric and physical activity and resting metabolic rate remained constant, the participants lost more mass after the KD than after the HCLF diet. The observed significant changes in triiodothyronine concentration suggest that unknown metabolic changes occur in nutritional ketosis, changes that warrant further investigation. TRIAL REGISTRATION Pan African Clinical Trial Registry: PACTR201707002406306 URL: https://pactr.samrc.ac.za/.
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Effects of the 5:2 intermittent fasting diet on non-alcoholic fatty liver disease: A randomized controlled trial.
Kord Varkaneh, H, Salehi Sahlabadi, A, Găman, MA, Rajabnia, M, Sedanur Macit-Çelebi, M, Santos, HO, Hekmatdoost, A
Frontiers in nutrition. 2022;9:948655
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Non-alcoholic fatty liver disease (NAFLD) is associated with modifiable risk factors such as obesity, diabetes and metabolic syndrome. The 5:2 diet is an intermittent fasting regimen in which you fast for two days and eat liberally for five days per week. Time-restricted eating or intermittent fasting is a great way to limit energy intake and manage metabolic markers, making fasting diets like the 5:2 a viable option for the treatment of NAFLD. In this study, fifty patients with NAFLD were randomly assigned to either the intermittent fasting (5:2) or the control group. In the 5:2 group, the intervention resulted in a modest reduction in calorie intake. Participants on the 5:2 diet showed significant improvements in biomarkers of NAFLD, inflammatory markers, and body composition after 12 weeks of intervention. An evaluation of the effectiveness of a 5:2 diet on improving lipid profiles and diabetes requires further robust research. This study provides healthcare professionals insight into the benefits of implementing intermittent fasting as a cost-effective and safe therapeutic method.
Abstract
Background and aims: Dietary regimens are crucial in the management of non-alcoholic fatty liver disease (NAFLD). The effects of intermittent fasting (IF) have gained attention in this regard, but further research is warranted. Thus, we aimed to ascertain the overall effects of the 5:2 IF diet (5 days a week of normal food intake and 2 consecutive fasting days) in patients with NAFLD compared to a control group (usual diet). Methods and results: A 12-week randomized controlled trial was performed to evaluate the effects of the 5:2 IF diet on anthropometric indices, body composition, liver indices, serum lipids, glucose metabolism, and inflammatory markers in patients with NAFLD. The IF group (n = 21) decreased body weight (86.65 ± 12.57-82.94 ± 11.60 kg), body mass index (30.42 ± 2.27-29.13 ± 1.95 kg/m2), waist circumference (103.52 ± 6.42-100.52 ± 5.64 cm), fat mass (26.64 ± 5.43-23.85 ± 5.85 kg), fibrosis (6.97 ± 1.94-5.58 ± 1.07 kPa), steatosis scores/CAP (313.09 ± 25.45-289.95 ± 22.36 dB/m), alanine aminotransferase (41.42 ± 20.98-28.38 ± 15.21 U/L), aspartate aminotransferase (34.19 ± 10.88-25.95 ± 7.26 U/L), triglycerides (171.23 ± 39.88-128.04 ± 34.88 mg/dl), high-sensitivity C-reactive protein (2.95 ± 0.62 -2.40 ± 0.64 mg/L), and cytokeratin-18 (1.32 ± 0.06-1.19 ± 0.05 ng/ml) values compared to the baseline and the end of the control group (n = 23)-p ≤ 0.05 were considered as significant. However, the intervention did not change the levels of high-density lipoprotein cholesterol, total cholesterol, low-density lipoprotein cholesterol, fasting blood sugar, insulin, HOMA-IR, and total antioxidant capacity. Conclusion: Adhering to the 5:2 IF diet can reduce weight loss and related parameters (fat mass and anthropometric indicators of obesity), as well as hepatic steatosis, liver enzymes, triglycerides, and inflammatory biomarkers in patients with NAFLD.
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The effectiveness of diet intervention in improving the metabolism of overweight and obese women: a systematic review and meta-analysis.
Chen, M, Chen, Q, Liu, W, Tong, H, Wu, Y
American journal of translational research. 2022;14(5):2926-2938
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At present, the treatment for obesity includes regular physical activity, diet intervention, medication and bariatric surgery. The aim of this study was to summarise the current literature and investigate whether different dietary interventions influence the metabolic indicators of overweight or obesity. This study is a systematic review and meta-analysis of twelve papers, eight of which were of medium quality. The duration of dietary therapy was usually an average of 19 weeks, from 4 weeks to 24 weeks. Dietary interventions included a calorie-restricted diet, a Mediterranean diet, a low-carb diet, a low-fat diet, and a ketogenic diet. Results show that dietary intervention had a significant effect on changes in fasting insulin, fasting glucose and insulin resistance changes in women. Additionally, dietary intervention also had a positive effect on triglycerides, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. Authors conclude that obese women should follow dietary interventions to improve their metabolic index. Furthermore, future large-scale randomised controlled trial experiments should be performed on specific diet therapies.
Abstract
OBJECTIVES Dietary therapy may improve glucose and lipid metabolism function in women. However, there is no systematic review to investigate the association between metabolic effects and different dietary interventions in obese women. The main purpose of this study is to summarize the current literature and investigate whether different dietary interventions have an effect on glucose and metabolic indicators of overweight or obese women. METHODS We conducted a scoping review of randomized controlled trial (RCT) studies from 1991 to 2022 by adopting a systematic review and meta-analysis. The database includes Google Scholar, PubMed, Embase and Web of Science. Literature screening, data extraction, and quality assessment were independently completed by 2 researchers. Meta-analysis was performed with RevMan. RESULTS Twelve articles were extracted and the meta-analysis results showed that the mean difference of metabolic indexes of obese women before and after dietary intervention, including fasting glucose, fasting insulin, HOMA-IR (Homeostasis model assessment-insulin resistance), TG (triglyceride), TC (total cholesterol), LDL-C (low-density lipoprotein cholesterol), HDL-C (high-density lipoprotein cholesterol) are -0.13 [-0.15, -0.10], -2.41 [-3.44, -1.38], -0.13 [-0.15, -0.10], -21.71 [-24.19, -19.22], -21.71 [-24.19, -19.22], -13.29 [-17.86, -8.72], 3.31 [2.22, 4.40], respectively. CONCLUSIONS Different dietary interventions benefit glucose and lipid metabolism of overweight or obese women. Further study is needed to determine which specific dietary effects have the greatest effect on improving metabolic indicators.
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The Effect of Ketogenic Diet on Shared Risk Factors of Cardiovascular Disease and Cancer.
Mohammadifard, N, Haghighatdoost, F, Rahimlou, M, Rodrigues, APS, Gaskarei, MK, Okhovat, P, de Oliveira, C, Silveira, EA, Sarrafzadegan, N
Nutrients. 2022;14(17)
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Cardiovascular disease and cancer are major causes of mortality worldwide and share common pathophysiological mechanisms and risk factors. The ketogenic diet, a low-carbohydrate and high-fat diet, may alter metabolic pathways, potentially lowering the risk of developing these diseases. Specifically, the ketogenic diet improves energy metabolism by promoting the use of body ketones for energy production. This review examines the protective effects of the ketogenic diet in reducing cardiovascular disease and cancer risk and explores the underlying mechanisms. The ketogenic diet may suppress oxidative stress and inflammation while improving common risk factors such as obesity, hypertension, diabetes, and dyslipidaemia. It is important to conduct further rigorous studies to assess the long-term effects of the ketogenic diet. However, healthcare professionals can use these findings to understand the short-term benefits of the diet in managing metabolic abnormalities and reducing the risk of developing cardiovascular disease and cancer.
Abstract
Cardiovascular disease (CVD) and cancer are the first and second leading causes of death worldwide, respectively. Epidemiological evidence has demonstrated that the incidence of cancer is elevated in patients with CVD and vice versa. However, these conditions are usually regarded as separate events despite the presence of shared risk factors between both conditions, such as metabolic abnormalities and lifestyle. Cohort studies suggested that controlling for CVD risk factors may have an impact on cancer incidence. Therefore, it could be concluded that interventions that improve CVD and cancer shared risk factors may potentially be effective in preventing and treating both diseases. The ketogenic diet (KD), a low-carbohydrate and high-fat diet, has been widely prescribed in weight loss programs for metabolic abnormalities. Furthermore, recent research has investigated the effects of KD on the treatment of numerous diseases, including CVD and cancer, due to its role in promoting ketolysis, ketogenesis, and modifying many other metabolic pathways with potential favorable health effects. However, there is still great debate regarding prescribing KD in patients either with CVD or cancer. Considering the number of studies on this topic, there is a clear need to summarize potential mechanisms through which KD can improve cardiovascular health and control cell proliferation. In this review, we explained the history of KD, its types, and physiological effects and discussed how it could play a role in CVD and cancer treatment and prevention.
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Effect of a Personalized Diet to Reduce Postprandial Glycemic Response vs a Low-fat Diet on Weight Loss in Adults With Abnormal Glucose Metabolism and Obesity: A Randomized Clinical Trial.
Popp, CJ, Hu, L, Kharmats, AY, Curran, M, Berube, L, Wang, C, Pompeii, ML, Illiano, P, St-Jules, DE, Mottern, M, et al
JAMA network open. 2022;5(9):e2233760
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Postprandial glycaemic response (PPGR) to foods can be different from person to person. This could be the reason why people experience different weight loss outcomes with standardised diets such as a low glycaemic index diet, low-fat diet or a low carbohydrate diet. In this single-centre, population-based, randomised, blinded clinical trial, 204 participants with irregular glucose metabolism and obesity were randomised to consume either a low-fat or personalised diet for six months in combination with fourteen behavioural change counselling sessions. The participants in the personalised diet group received a colour-coded meal score to indicate their estimated PPGR for different foods. The results of this study showed no significant weight reduction in the personalised diet group compared to the low-fat diet. Further robust studies are required to develop appropriate precision nutrition interventions for weight loss and energy balance. However, healthcare professionals can use the results of this study to understand that both a low-fat diet and a personalised diet, coupled with behavioural counselling, may be effective in promoting weight loss in obese populations with irregular glucose metabolism.
Abstract
IMPORTANCE Interindividual variability in postprandial glycemic response (PPGR) to the same foods may explain why low glycemic index or load and low-carbohydrate diet interventions have mixed weight loss outcomes. A precision nutrition approach that estimates personalized PPGR to specific foods may be more efficacious for weight loss. OBJECTIVE To compare a standardized low-fat vs a personalized diet regarding percentage of weight loss in adults with abnormal glucose metabolism and obesity. DESIGN, SETTING, AND PARTICIPANTS The Personal Diet Study was a single-center, population-based, 6-month randomized clinical trial with measurements at baseline (0 months) and 3 and 6 months conducted from February 12, 2018, to October 28, 2021. A total of 269 adults aged 18 to 80 years with a body mass index (calculated as weight in kilograms divided by height in meters squared) ranging from 27 to 50 and a hemoglobin A1c level ranging from 5.7% to 8.0% were recruited. Individuals were excluded if receiving medications other than metformin or with evidence of kidney disease, assessed as an estimated glomerular filtration rate of less than 60 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration equation, to avoid recruiting patients with advanced type 2 diabetes. INTERVENTIONS Participants were randomized to either a low-fat diet (<25% of energy intake; standardized group) or a personalized diet that estimates PPGR to foods using a machine learning algorithm (personalized group). Participants in both groups received a total of 14 behavioral counseling sessions and self-monitored dietary intake. In addition, the participants in the personalized group received color-coded meal scores on estimated PPGR delivered via a mobile app. MAIN OUTCOMES AND MEASURES The primary outcome was the percentage of weight loss from baseline to 6 months. Secondary outcomes included changes in body composition (fat mass, fat-free mass, and percentage of body weight), resting energy expenditure, and adaptive thermogenesis. Data were collected at baseline and 3 and 6 months. Analysis was based on intention to treat using linear mixed modeling. RESULTS Of a total of 204 adults randomized, 199 (102 in the personalized group vs 97 in the standardized group) contributed data (mean [SD] age, 58 [11] years; 133 women [66.8%]; mean [SD] body mass index, 33.9 [4.8]). Weight change at 6 months was -4.31% (95% CI, -5.37% to -3.24%) for the standardized group and -3.26% (95% CI, -4.25% to -2.26%) for the personalized group, which was not significantly different (difference between groups, 1.05% [95% CI, -0.40% to 2.50%]; P = .16). There were no between-group differences in body composition and adaptive thermogenesis; however, the change in resting energy expenditure was significantly greater in the standardized group from 0 to 6 months (difference between groups, 92.3 [95% CI, 0.9-183.8] kcal/d; P = .05). CONCLUSIONS AND RELEVANCE A personalized diet targeting a reduction in PPGR did not result in greater weight loss compared with a low-fat diet at 6 months. Future studies should assess methods of increasing dietary self-monitoring adherence and intervention exposure. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03336411.