Can a Higher Protein/Low Glycemic Index vs. a Conventional Diet Attenuate Changes in Appetite and Gut Hormones Following Weight Loss? A 3-Year PREVIEW Sub-study

Background: Previous research showed that weight-reducing diets increase appetite sensations and/or circulating ghrelin concentrations for up to 36 months, with transient or enduring perturbations in circulating concentrations of the satiety hormone peptide YY.

Objective: This study assessed whether a diet that is higher in protein and low in glycemic index (GI) may attenuate these changes.

Methods: 136 adults with pre-diabetes and a body mass index of ≥25 kg/m² underwent a 2-month weight-reducing total meal replacement diet. Participants who lost ≥8% body weight were randomized to one of two 34-month weight-maintenance diets: a higher-protein and moderate-carbohydrate (CHO) diet with low GI, or a moderate-protein and higher-CHO diet with moderate GI. Both arms involved recommendations to increase physical activity. Fasting plasma concentrations of total ghrelin and total peptide YY, and appetite sensations, were measured at 0 months (pre-weight loss), at 2 months (immediately post-weight loss), and at 6, 12, 24, and 36 months.

Results: There was a decrease in plasma peptide YY concentrations and an increase in ghrelin after the 2-month weight-reducing diet, and these values approached pre-weight-loss values by 6 and 24 months, respectively (P = 0.32 and P = 0.08, respectively, vs. 0 months). However, there were no differences between the two weight-maintenance diets. Subjective appetite sensations were not affected by the weight-reducing diet nor the weight-maintenance diets. While participants regained an average of ~50% of the weight they had lost by 36 months, the changes in ghrelin and peptide YY during the weight-reducing phase did not correlate with weight regain.

Conclusion: A higher-protein, low-GI diet for weight maintenance does not attenuate changes in ghrelin or peptide YY compared with a moderate-protein, moderate-GI diet.

Clinical Trial Registry:ClinicalTrials.gov registry ID NCT01777893 (PREVIEW) and ID NCT02030249 (Sub-study).

Urine dipsticks are not accurate for detecting mild ketosis during a severely energy restricted diet

Background

Detection of the mild ketosis induced by severely energy‐restricted diets may be a clinically useful way to monitor and promote dietary adherence. Mild ketosis is often assessed using urine dipsticks, but accuracy for this purpose has not been tested.

Objective

To determine the accuracy of urine dipsticks to detect mild ketosis during adherence to a severely energy‐restricted diet.

Methods

Two hundred and sixty three (263) fasting urine and 263 fasting blood samples were taken from 50 women (mean [standard deviation, SD] age 58.0 [4.3] years and body mass index 34.3 [2.4] kg/m²) before and at six time points during or for up to 10 weeks after 16 weeks of severe energy restriction, achieved with a total meal replacement diet. The amount of ketones (acetoacetate) in the urine was classified as ‘0 (Negative)’, ‘+/− (Trace)’, ‘+ (Weak)’ or ‘++ (Medium)’ by urine dipsticks (Ketostix, Bayer). The concentration of ketones (β‐hydroxybutyrate) in the blood was measured with our reference method, a portable ketone monitor (FreeStyle Optium, Abbott). The diagnostic accuracy of the urine dipsticks was assessed from the percent of instances when a person was actually ‘in ketosis’ (as defined by a blood β‐hydroxybutyrate concentration at or above three different thresholds) that were also identified by the urine dipsticks as being from a person in ketosis (the percent ‘true positives’ or sensitivity), as well as the percent of instances when a person was not in ketosis (as defined by the blood monitor result) was correctly identified as such with the urine dipstick (the percent ‘true negatives’ or specificity). Thresholds of ≥0.3mM, ≥0.5mM or ≥1.0mM were selected, because mean blood concentrations of β‐hydroxybutyrate during ketogenic diets are approximately 0.5mM. Sensitivity and specificity were then used to generate receiver operating characteristic curves, with the area under these curves indicating the ability of the dipsticks to correctly identify people in ketosis (1 = perfect results, 0.5 = random results).

Results

At threshold blood β‐hydroxybutyrate concentrations of ≥0.3mM, ≥0.5mM and ≥1.0mM, the sensitivity of the urine dipsticks was 35%, 52% and 76%; the specificity was 100%, 97% and 78%; and the area under the receiver operating characteristic curves was 0.67, 0.74 and 0.77, respectively. These low levels of sensitivity mean that 65%, 48% or 24% of the instances when a person was in ketosis were not detected by the urine dipsticks.

Conclusion

Urine dipsticks are not an accurate or clinically useful means of detecting mild ketosis in people undergoing a severely energy‐restricted diet and should thus not be recommended in clinical treatment protocols. If monitoring of mild ketosis is indicated (eg, to monitor or help promote adherence to a severely energy‐restricted diet), then blood monitors should be used instead.

3-Year effect of weight loss via severe versus moderate energy restriction on body composition among postmenopausal women with obesity - the TEMPO Diet Trial

We have previously shown that a severely energy-restricted diet leads to greater loss of weight, fat, lean mass and bone mineral density (BMD) at 12 months in postmenopausal women with obesity than a moderately energy-restricted diet. We now aim to evaluate whether these effects are sustained longer term (ie, at 36 months). 101 postmenopausal women were randomized to either 12 months of moderate (25 to 35%) energy restriction with a food-based diet (moderate intervention), or 4 months of severe (65 to 75%) energy restriction with a total meal replacement diet followed by moderate energy restriction for 8 months (severe intervention). Body weight and composition were measured at 0, 24 and 36 months. Participants in the severe intervention lost ~1.5 to 1.7 times as much weight, waist circumference, whole-body fat mass and visceral adipose tissue compared to those in the moderate intervention, and were 2.6 times more likely (42% versus 16%) to have lost 10% or more of their initial body weight at 36 months (P < 0.01 for all). However, those in the severe versus moderate intervention lost ~1.4 times as much whole-body lean mass (P < 0.01), albeit this was proportional to total weight lost and there was no greater loss of handgrip strength, and they also lost ~2 times as much total hip BMD between 0 and 36 months (P < 0.05), with this bone loss occurring in the first 12 months. Thus, severe energy restriction is more effective than moderate energy restriction for reducing weight and adiposity in postmenopausal women in the long term (3 years), but attention to BMD loss in the first year is required.

Trial registration

Australian New Zealand Clinical Trials Registry Reference Number: 12612000651886, anzctr.org.au.

Effect of Weight Loss via Severe vs Moderate Energy Restriction on Lean Mass and Body Composition Among Postmenopausal Women With Obesity: The TEMPO Diet Randomized Clinical Trial

IMPORTANCE

Severely energy-restricted diets are the most effective dietary obesity treatment. However, there are concerns regarding potential adverse effects on body composition.

OBJECTIVE

To compare the long-term effects of weight loss via severe vs moderate energy restriction on lean mass and other aspects of body composition.

DESIGN, SETTING, AND PARTICIPANTS

The Type of Energy Manipulation for Promoting Optimum Metabolic Health and Body Composition in Obesity (TEMPO) Diet Trial was a 12-month, single-center, randomized clinical trial. A total of 101 postmenopausal women, aged 45 to 65 years with body mass index (calculated as weight in kilograms divided by height in meters squared) from 30 to 40, who were at least 5 years after menopause, had fewer than 3 hours of structured physical activity per week, and lived in the Sydney metropolitan area of New South Wales, Australia, were recruited between March 2013 and July 2016. Data analysis was conducted between October 2018 and August 2019.

INTERVENTION

Participants were randomized to either 12 months of moderate (25%-35%) energy restriction with a food-based diet (moderate intervention) or 4 months of severe (65%-75%) energy restriction with a total meal replacement diet followed by moderate energy restriction for an additional 8 months (severe intervention). Both interventions had a prescribed protein intake of 1.0 g/kg of actual body weight per day, and physical activity was encouraged but not supervised.

MAIN OUTCOMES AND MEASURES

The primary outcome was whole-body lean mass at 12 months after commencement of intervention. Secondary outcomes were body weight, thigh muscle area and muscle function (strength), bone mineral density, and fat mass and distribution, measured at 0, 4, 6, and 12 months.

RESULTS

A total of 101 postmenopausal women were recruited (mean [SD] age, 58.0 [4.2] years; mean [SD] weight, 90.8 [9.1] kg; mean [SD] body mass index, 34.4 [2.5]). Compared with the moderate group at 12 months, the severe group lost more weight (effect size, -6.6 kg; 95% CI, -8.2 to -5.1 kg), lost more whole-body lean mass (effect size, -1.2 kg; 95% CI, -2.0 to -0.4 kg), and lost more thigh muscle area (effect size, -4.2 cm2; 95% CI, -6.5 to -1.9 cm2). However, decreases in whole-body lean mass and thigh muscle area were proportional to total weight loss, and there was no difference in muscle (handgrip) strength between groups. Total hip bone mineral density (effect size, -0.017 g/cm2; 95% CI, -0.029 to -0.005 g/cm2), whole-body fat mass (effect size, -5.5 kg; 95% CI, -7.1 to -3.9 kg), abdominal subcutaneous adipose tissue (effect size, -1890 cm3; 95% CI, -2560 to -1219 cm3), and visceral adipose tissue (effect size, -1389 cm3; 95% CI, -1748 to -1030 cm3) loss were also greater for the severe group than for the moderate group at 12 months.

CONCLUSIONS AND RELEVANCE

Severe energy restriction had no greater adverse effect on relative whole-body lean mass or handgrip strength compared with moderate energy restriction and was associated with 2-fold greater weight and fat loss over 12 months. However, there was significantly greater loss of total hip bone mineral density with severe vs moderate energy restriction. Therefore, caution is necessary when implementing severe energy restriction in postmenopausal women, particularly those with osteopenia or osteoporosis.

TRIAL REGISTRATION

anzctr.org.au Identifier: 12612000651886.

Less Waste on Waist Measurements: Determination of Optimal Waist Circumference Measurement Site to Predict Visceral Adipose Tissue in Postmenopausal Women with Obesity

With obesity being a leading cause of preventable death, it is vital to understand how best to identify individuals with greater risk of metabolic disease, especially those with high visceral adipose tissue (VAT). This study aimed to determine whether three commonly used waist circumference (WC) measurement sites could provide accurate estimations of VAT, as determined by magnetic resonance imaging (MRI), which is a gold standard for measuring VAT, in postmenopausal women with obesity. VAT volume was measured by MRI of the total abdomen in 97 women aged 57.7 ± 0.4 years (mean ± SEM), mean body mass index 34.5 ± 0.2 kg/m². WC was measured at the midpoint between the lowest rib and the iliac crest (WC_mid), the narrowest point of the torso (WC_narrow), and at the level of the umbilicus (WC_umbilicus). WC differed significantly according to measurement site, with WC_narrow (102.1 ± 0.7 cm) < WC_mid (108.3 ± 0.7 cm) < WC_umbilicus (115.7 ± 0.8 cm) (p < 0.001). WC_mid, WC_narrow and WC_umbilicus were all significantly correlated with VAT, as measured by MRI (r = 0.581, 0.563 and 0.390, respectively; p < 0.001 for all), but the relationships between WC_mid or WC_narrow and VAT determined by MRI were stronger than for WC_umbilicus. Measurement of either WC_mid or WC_narrow provides valid estimates of VAT in postmenopausal women with obesity, with WC_narrow being favoured in light of its greater ease and speed of measurement in this population.

Technical note: Whole-genome amplification of DNA extracted from cattle semen samples

The bovine genome sequence project and the discovery of many thousands of bovine single nucleotide polymorphisms has opened the door for large-scale genotyping studies to identify genes that contribute to economically important traits with relevance to the beef and dairy industries. Large amounts of DNA will be required for these research projects. This study reports the use of the whole-genome amplification (WGA) method to create an unlimited supply of DNA for use in genotyping studies and long-term storage for future gene discovery projects. Two commercial WGA kits (GenomiPhi, Amersham Biosciences, Sydney, Australia, and REPLI-g, Qiagen, Doncaster, Australia) were used to amplify DNA from straws of bull semen, resulting in an average of 7.2 and 67 microg of DNA per reaction, respectively. The comparison of 3.5 kb of sequences from the amplified and unamplified DNA indicated no detectable DNA differences. Similarly, gene marker analysis conducted on genomic DNA and DNA after WGA indicated no difference in marker amplification or clarity and accuracy of scoring for approximately 10,000 single nucleotide polymorphism markers when compared with WGA samples genotyped in duplicate. These results illustrate that WGA is a suitable method for the amplification and recovery of DNA from bull semen samples for routine genomic investigations.

Computer-assisted method development and optimization in high-performance liquid chromatography

This paper reports the use of DryLab, a computer simulation software package, to assist in the development and optimization of a reversed-phase high-performance liquid chromatographic (HPLC) method for the separation of a model drug candidate and its degradation products. Prior to the optimization process, columns with various bonded phases are evaluated for their chromatographic performance using the sample of interest. Simultaneous optimization of two separation variables and the use of resolution maps to predict the optimal conditions are illustrated. Options to optimize column conditions (column length and flow-rate) to further reduce run time are briefly discussed. The accuracy of DryLab-predicted retention times and resolution is compared with experimental values. The DryLab software used in this study provided satisfactory predictions for the selected model, with average errors of less than 3.5 and 11.8% for retention time and resolution, respectively.

Application of pressurized liquid extraction technology to pharmaceutical solid dosage form analysis

The technique of pressurized liquid extraction has been evaluated for the extraction of active ingredients from pharmaceutical dosage forms using montelukast sodium oral chewable tablets as a model. The extraction method was optimized for the number of extraction cycles, extraction time, extraction solvent composition and temperature. Samples were extracted using two cycles of water for 2 min with a cell temperature of 40 degrees C and a pressure of 1.0 x 10(4) kPa, to disintegrate the tablet, followed by three cycles of methanol for 3 min at 70 degrees C and 1.0 x 10(4) kPa, to solubilize montelukast sodium. The method demonstrated an extraction efficiency of 98.2% of label claim and an RSD of 1.3% (n=10), as compared to 97.6% and an RSD of 0.9% obtained using a validated mechanical extraction method.

A comparison of piglet production and survival in the Werribee Farrowing Pen and conventional farrowing crates at a commercial farm

The ‘Werribee Farrowing Pen’, which was developed as a loose housing alternative to the conventional farrowing crate for sows and litters, was evaluated as a practical alternative to farrowing crates. Four Werribee Farrowing Pens and 5 crates were installed side-by-side in an uninsulated grower pig shed at a commercial farm. The trial was conducted over 18 months and involved 17 batches of sows with a total of 146 commercial Pig Improvement Company Camborough sows and litters, 66 in Werribee Farrowing Pens and 80 in crates. The sows ranged in parity number from 1 to 8 (mean s.d., 2.8 1.77). Staff conducted an internal examination of sows at farrowing to manually deliver piglets half as often (P<0.05) in the Werribee Farrowing Pen compared to the crate treatment (13.6% v. 27.5% of sows, respectively). Whether this difference reflected a greater incidence of farrowing problems for crate treatment sows, or a reduced willingness by piggery staff to interfere with unrestrained sows in the Werribee Farrowing Pen treatment, is not known. There were no differences due to the farrowing system on the number of piglets born per sow (11.5 piglets) or weaned (9.4 piglets). Sows were fed ‘to appetite’ after the first week of lactation, and in 6 farrowing batches, the quantity of feed provided to sows each day was measured. Werribee Farrowing Pen compared to crate treatment sows received more feed (P<0.01) in week 3 of lactation (55.0 v. 48.2 kg/sow.week). We conclude that although piglet production and survival rates were similar in the two systems, the main disadvantage of the Werribee Farrowing Pen for intensive pig buildings, viz. extra floor space required per sow, may be partly offset by improved feed intakes by sows later in lactation.

Popliteal vein aneurysm: an unusual source of pulmonary embolus

A 78 year old woman developed repeated major pulmonary emboli following nasal resection for recurrent basal cell carcinoma. Lower extremity venography performed prior to planned insertion of an inferior vena caval filter unexpectedly revealed a large thrombus-containing aneurysm of the proximal popliteal vein. The aneurysm was excised and the vein repaired by lateral suture. Anticoagulation was continued for 3 months postoperatively. There were no further episodes of pulmonary embolism and popliteal vein patency was confirmed by duplex ultrasound 3 months postoperatively. The literature pertaining to these rare popliteal venous aneurysms is reviewed.

Myocardial and aerobic requirements for an upper body exerciser: implications for cardiac rehabilitation

To assess the cardiorespiratory, hemodynamic, and electrocardiograph (ECG) responses to an upper body exercise device, we studied ten cardiac men (mean age +/- SD = 58.0 +/- 6.5 years) who performed three five-minute exercise bouts at metronome settings of 20, 50, and 80 clicks per minute. Operation of the device involved shuttling a plastic buoy on two 6-m waxed ropes between two persons. Aerobic requirements were generally appropriate for arm training, corresponding to mean values of 5.3, 7.0, and 10.1 ml.kg-1.min-1 at the three progressive metronome settings. Perceived exertion (Borg, 6 to 20 scale) at these work rates was 8.3, 10.4, and 14.6, whereas average heart rate and systolic blood pressure responses were 77, 85, and 114 beats.min-1 and 145, 158, and 175 mmHg, respectively. Continuous ECG monitoring during upper body exercise revealed no significant ST-segment depression or serious arrhythmias. The device appears to be a safe and effective complement to a cardiac exercise training program.