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Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial.
Gardner, CD, Trepanowski, JF, Del Gobbo, LC, Hauser, ME, Rigdon, J, Ioannidis, JPA, Desai, M, King, AC
JAMA. 2018;319(7):667-679
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Obesity is a major public health challenge and different dietary strategies are employed to lose weight. This randomised clinical trial of 609 obese adults between the age of 18 and 50 aimed to determine the effects of a healthy low-fat diet in comparison to a healthy low-carbohydrate diet on weight change over a 12 month period. The study also assessed whether 3 genetic markers and blood sugar management affected weight loss in the 2 groups. Participants in the study were offered 22 group sessions of health coaching to support adherence to the programme. 481 participants completed the study. The low-carbohydrate group lost on average 6kg and the low-fat group lost on average 5.4kg. The difference between the 2 groups did not achieve significance for weight loss. There was also no significant genetic or blood sugar management effect in relation to dietary pattern and weight loss. The authors of this study conclude that the results of this study do not help in identifying which dietary type is better for whom in relation to 3 genetic markers and blood sugar management.
Abstract
Importance: Dietary modification remains key to successful weight loss. Yet, no one dietary strategy is consistently superior to others for the general population. Previous research suggests genotype or insulin-glucose dynamics may modify the effects of diets. Objective: To determine the effect of a healthy low-fat (HLF) diet vs a healthy low-carbohydrate (HLC) diet on weight change and if genotype pattern or insulin secretion are related to the dietary effects on weight loss. Design, Setting, and Participants: The Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) randomized clinical trial included 609 adults aged 18 to 50 years without diabetes with a body mass index between 28 and 40. The trial enrollment was from January 29, 2013, through April 14, 2015; the date of final follow-up was May 16, 2016. Participants were randomized to the 12-month HLF or HLC diet. The study also tested whether 3 single-nucleotide polymorphism multilocus genotype responsiveness patterns or insulin secretion (INS-30; blood concentration of insulin 30 minutes after a glucose challenge) were associated with weight loss. Interventions: Health educators delivered the behavior modification intervention to HLF (n = 305) and HLC (n = 304) participants via 22 diet-specific small group sessions administered over 12 months. The sessions focused on ways to achieve the lowest fat or carbohydrate intake that could be maintained long-term and emphasized diet quality. Main Outcomes and Measures: Primary outcome was 12-month weight change and determination of whether there were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss. Results: Among 609 participants randomized (mean age, 40 [SD, 7] years; 57% women; mean body mass index, 33 [SD, 3]; 244 [40%] had a low-fat genotype; 180 [30%] had a low-carbohydrate genotype; mean baseline INS-30, 93 μIU/mL), 481 (79%) completed the trial. In the HLF vs HLC diets, respectively, the mean 12-month macronutrient distributions were 48% vs 30% for carbohydrates, 29% vs 45% for fat, and 21% vs 23% for protein. Weight change at 12 months was -5.3 kg for the HLF diet vs -6.0 kg for the HLC diet (mean between-group difference, 0.7 kg [95% CI, -0.2 to 1.6 kg]). There was no significant diet-genotype pattern interaction (P = .20) or diet-insulin secretion (INS-30) interaction (P = .47) with 12-month weight loss. There were 18 adverse events or serious adverse events that were evenly distributed across the 2 diet groups. Conclusions and Relevance: In this 12-month weight loss diet study, there was no significant difference in weight change between a healthy low-fat diet vs a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In the context of these 2 common weight loss diet approaches, neither of the 2 hypothesized predisposing factors was helpful in identifying which diet was better for whom. Trial Registration: clinicaltrials.gov Identifier: NCT01826591.
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Effect of an Intensive Lifestyle Intervention on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Clinical Trial.
Johansen, MY, MacDonald, CS, Hansen, KB, Karstoft, K, Christensen, R, Pedersen, M, Hansen, LS, Zacho, M, Wedell-Neergaard, AS, Nielsen, ST, et al
JAMA. 2017;318(7):637-646
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First-line treatment of Type 2 diabetes includes diet, physical activity, and weight loss prior to or in parallel with initiation of medication. The aim of this study was to examine whether an intensive lifestyle intervention results in equivalent blood sugar control compared with standard care. A secondary aim was to test whether an intensive lifestyle intervention leads to a reduction in glucose-lowering medication in participants with Type 2 diabetes. The study was a randomized, assessor-blind clinical study of 98 adults with Type 2 diabetes diagnosed for less than 10 years. The participants were randomly assigned (2:1; stratified by sex) to the lifestyle group (n = 64) or the standard care group (n = 34). Results show that an intensive lifestyle intervention did not achieve comparable blood sugar control in comparison with standard care, however, the former led to a substantial and parallel reduction in glucose-lowering medication. The authors conclude that even though a lifestyle intervention compared to standard care did not result in the expected glycaemic control, it was still in a direction consistent with benefit.
Abstract
Importance: It is unclear whether a lifestyle intervention can maintain glycemic control in patients with type 2 diabetes. Objective: To test whether an intensive lifestyle intervention results in equivalent glycemic control compared with standard care and, secondarily, leads to a reduction in glucose-lowering medication in participants with type 2 diabetes. Design, Setting, and Participants: Randomized, assessor-blinded, single-center study within Region Zealand and the Capital Region of Denmark (April 2015-August 2016). Ninety-eight adult participants with non-insulin-dependent type 2 diabetes who were diagnosed for less than 10 years were included. Participants were randomly assigned (2:1; stratified by sex) to the lifestyle group (n = 64) or the standard care group (n = 34). Interventions: All participants received standard care with individual counseling and standardized, blinded, target-driven medical therapy. Additionally, the lifestyle intervention included 5 to 6 weekly aerobic training sessions (duration 30-60 minutes), of which 2 to 3 sessions were combined with resistance training. The lifestyle participants received dietary plans aiming for a body mass index of 25 or less. Participants were followed up for 12 months. Main Outcomes and Measures: Primary outcome was change in hemoglobin A1c (HbA1c) from baseline to 12-month follow-up, and equivalence was prespecified by a CI margin of ±0.4% based on the intention-to-treat population. Superiority analysis was performed on the secondary outcome reductions in glucose-lowering medication. Results: Among 98 randomized participants (mean age, 54.6 years [SD, 8.9]; women, 47 [48%]; mean baseline HbA1c, 6.7%), 93 participants completed the trial. From baseline to 12-month follow-up, the mean HbA1c level changed from 6.65% to 6.34% in the lifestyle group and from 6.74% to 6.66% in the standard care group (mean between-group difference in change of -0.26% [95% CI, -0.52% to -0.01%]), not meeting the criteria for equivalence (P = .15). Reduction in glucose-lowering medications occurred in 47 participants (73.5%) in the lifestyle group and 9 participants (26.4%) in the standard care group (difference, 47.1 percentage points [95% CI, 28.6-65.3]). There were 32 adverse events (most commonly musculoskeletal pain or discomfort and mild hypoglycemia) in the lifestyle group and 5 in the standard care group. Conclusions and Relevance: Among adults with type 2 diabetes diagnosed for less than 10 years, a lifestyle intervention compared with standard care resulted in a change in glycemic control that did not reach the criterion for equivalence, but was in a direction consistent with benefit. Further research is needed to assess superiority, as well as generalizability and durability of findings. Trial Registration: clinicaltrials.gov Identifier: NCT02417012.
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Effects of fasting and preoperative feeding in children.
Yurtcu, M, Gunel, E, Sahin, TK, Sivrikaya, A
World journal of gastroenterology. 2009;15(39):4919-22
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Preoperative fasting is usually carried out to prevent the risk of vomiting during anaesthesia. The study investigated whether children should have a long period of fasting before surgery. Eight groups of 10 children (aged 1-10 years) with disorders of groin and scrotum were orally fed normal liquid food (NLF) or a high calorie diet (HCD) in 2 divided doses at 6 hour intervals, then fasted for 2, 3, 4 or 5 hours prior to surgery. Four groups had NLF and 4 groups had HCD. All children had their glucose, prealbumin and cortisol levels measured twice, just after the oral feeding and just before surgery. Once anaesthesia was sufficient and stable, gastric liquid was collected and measured. Patients with disease that could delay gastric emptying, had high acid production or were on medication were excluded from the trial. The researchers found that there was no significant difference in blood prealbumin levels in all groups. There was significant increase in blood cortisol in 4 groups when fasted (NLF-2h fasted, HCD-2h fasted, NLF-3h fasted and HCD-5h fasted). Stomach aid residue liquids were at tolerable levels of 1-2ml in all children. Anaesthesia was uneventful, with no coughing, laryngospasm or vomiting reported, and outcomes of surgery and wound healing were not affected. The authors noted that drinking clear liquids up to 2 hours before surgery was unlikely to substantially affect the volume of gastric fluids, and did not appear to increase the risk of vomiting in normal, healthy children. Glucose and insulin infusions appeared to minimise endocrine stress response and normalised post-op insulin sensitivity. Additionally, there may be a psychological benefit for children as irritability appeared to decrease prior to surgery. The study concluded that there was no need for fasting longer than 2 hours prior to inguinoscrotal region surgery.
Abstract
AIM: To investigate whether children should undergo surgery without a long period of fasting after feeding. METHODS Eighty children with inguinoscrotal disorders (aged 1-10 years) were studied prospectively. They were divided into eight groups that each contained 10 children who were fed normal liquid food (NLF) and a high-calorie diet (HCD) 2, 3, 4 and 5 h before surgery, in two doses at 6-h intervals. NLF was given to four groups and HCD to the other four. In all groups, glucose, prealbumin and cortisol levels in the blood were measured twice: just after oral feeding and just before the operation. After the establishment of adequate anesthesia, gastric residue liquid was measured with a syringe. RESULTS Blood glucose levels in all patients fed NLF and HCD were high, except in patients in the HCD-4 group. There was no significant difference in the blood prealbumin levels. There was a significant increase in the blood cortisol levels in the NLF-2 (14.4 +/- 5.7), HCD-2 (13.2 +/- 6.0), NLF-3 (10.9 +/- 6.4), and HCD-5 (6.8 +/- 5.7) groups (P < 0.05). CONCLUSION The stress of surgery may be tolerated by children when they are fed up to 2 h before elective surgery.