Dataset Information

Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets.

ABSTRACT:

Objective

This study aimed to compare self-reported with objective measurements of energy intake changes (?EI) during a 1-year weight-loss intervention with subjects randomized to low-carbohydrate versus low-fat diets.

Methods

Repeated body weight measurements were used as inputs to an objective mathematical model to calculate ?EI_Model and to compare with self-reported energy intake changes assessed by repeated 24-hour recalls (?EI_Recall ).

Results

?EI_Recall indicated a relatively persistent state of calorie restriction of ~500 to 600 kcal/d at 3, 6, and 12 months with no significant differences between the diets. ?EI_Model demonstrated large early decreases in calorie intake > 800 kcal/d followed by an exponential return to ~100 kcal/d below baseline at the end of the year. Accounting for self-reported physical activities did not materially affect the results. Discrepancies between ?EI_Model and ?EI_Recall became progressively greater over time. The low-carbohydrate diet resulted in ?EI_Model that was 162 ± 53 kcal/d lower than the low-fat diet over the first 3 months (P? = ?0.002), but no significant diet differences were found thereafter.

Conclusions

Self-reported ?EI measurements were inaccurate. Model-based calculations of ?EI found that instructions to follow the low-carbohydrate diet resulted in greater calorie restriction than the low-fat diet in the early phases of the intervention, but these diet differences were not sustained.

SUBMITTER: Guo J

PROVIDER: S-EPMC6392435 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Publications

Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets.

Guo Juen J Robinson Jennifer L JL Gardner Christopher D CD Hall Kevin D KD

Obesity (Silver Spring, Md.) 20190122 3

<h4>Objective</h4>This study aimed to compare self-reported with objective measurements of energy intake changes (∆EI) during a 1-year weight-loss intervention with subjects randomized to low-carbohydrate versus low-fat diets.<h4>Methods</h4>Repeated body weight measurements were used as inputs to an objective mathematical model to calculate ∆EI<sub>Model</sub> and to compare with self-reported energy intake changes assessed by repeated 24-hour recalls (∆EI<sub>Recall</sub> ).<h4>Results</h4>∆EI ...[more]

PMID: 30672127

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Project description:BACKGROUND:Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations. OBJECTIVE:To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors. DESIGN:A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271). SETTING:A large academic medical center. PARTICIPANTS:148 men and women without clinical cardiovascular disease and diabetes. INTERVENTION:A low-carbohydrate (<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7% saturated fat]) diet. Both groups received dietary counseling at regular intervals throughout the trial. MEASUREMENTS:Data on weight, cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months. RESULTS:Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, -3.5 kg [95% CI, -5.6 to -1.4 kg]; P = 0.002), fat mass (mean difference in change, -1.5% [CI, -2.6% to -0.4%]; P = 0.011), ratio of total-high-density lipoprotein (HDL) cholesterol (mean difference in change, -0.44 [CI, -0.71 to -0.16]; P = 0.002), and triglyceride level (mean difference in change, -0.16 mmol/L [-14.1 mg/dL] [CI, -0.31 to -0.01 mmol/L {-27.4 to -0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet. LIMITATION:Lack of clinical cardiovascular disease end points. CONCLUSION:The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors. PRIMARY FUNDING SOURCE:National Institutes of Health.

Project description:ImportanceIt is crucial to incorporate quality and types of carbohydrate and fat when investigating the associations of low-fat and low-carbohydrate diets with mortality.ObjectiveTo investigate the associations of low-carbohydrate and low-fat diets with total and cause-specific mortality among US adults.Design, setting, and participantsThis prospective cohort study used data from the US National Health and Nutrition Examination Survey from 1999 to 2014 from 37 233 adults 20 years or older with 24-hour dietary recall data. Data were analyzed from July 5 to August 27, 2019.ExposuresOverall, unhealthy, and healthy low-carbohydrate-diet and low-fat-diet scores based on the percentage of energy as total and subtypes of carbohydrate, fat, and protein.Main outcomes and measuresAll-cause mortality from baseline until December 31, 2015, linked to National Death Index mortality data.ResultsA total of 37 233 US adults (mean [SD] age, 49.7 [18.3] years; 19 598 [52.6%] female) were included in the present analysis. During 297 768 person-years of follow-up, 4866 total deaths occurred. Overall low-carbohydrate-diet and low-fat-diet scores were not associated with total mortality. The multivariable-adjusted hazard ratios for total mortality per 20-percentile increase in dietary scores were 1.07 (95% CI, 1.02-1.11; P = .01 for trend) for unhealthy low-carbohydrate-diet score, 0.91 (95% CI, 0.87-0.95; P < .001 for trend) for healthy low-carbohydrate-diet score, 1.06 (95% CI, 1.01-1.12; P = .04 for trend) for unhealthy low-fat-diet score, and 0.89 (95% CI, 0.85-0.93; P < .001 for trend) for healthy low-fat-diet score. The associations remained similar in the stratification and sensitivity analyses.Conclusions and relevanceIn this study, overall low-carbohydrate-diet and low-fat-diet scores were not associated with total mortality. Unhealthy low-carbohydrate-diet and low-fat-diet scores were associated with higher total mortality, whereas healthy low-carbohydrate-diet and low-fat-diet scores were associated with lower total mortality. These findings suggest that the associations of low-carbohydrate and low-fat diets with mortality may depend on the quality and food sources of macronutrients.

Project description:OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.

Dataset Information

Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets.

Objective

Methods

Results

Conclusions

Publications

Objective versus Self-Reported Energy Intake Changes During Low-Carbohydrate and Low-Fat Diets.

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