Ian Macdonald

Ian Macdonald
University of Nottingham | Notts · School of Life Sciences

BSc PhD

About

565
Publications
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Publications

Publications (565)
Article
OBJECTIVE To examine whether the effect of a 3-year lifestyle intervention on body weight and cardiometabolic risk factors differs by prediabetes metabolic phenotype. RESEARCH DESIGN AND METHODS This post hoc analysis of the multicenter, randomized trial, PREVention of diabetes through lifestyle interventions and population studies In Europe and a...
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Aims/hypothesis Lifestyle interventions are the first-line treatment option for body weight and cardiometabolic health management. However, whether age groups or women and men respond differently to lifestyle interventions is under debate. We aimed to examine age- and sex-specific effects of a low-energy diet (LED) followed by a long-term lifestyle...
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Behavioural responses to hypoglycaemia require coordinated recruitment of broadly distributed networks of interacting brain regions. We investigated hypoglycaemia-related changes in brain connectivity in people without diabetes (ND) and with type 1 diabetes with normal (NAH) or impaired (IAH) hypoglycaemia awareness. Two-step hyperinsulinaemic hypo...
Article
Background & aims Low-energy diet replacement is an effective tool to induce large and rapid weight loss and improve metabolic health, but in the long-term individuals often experience significant weight regain. Little is known about the role of animal-based foods in weight maintenance and metabolic health. We aimed to examine longitudinal associat...
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Due to the observations of weight loss at high altitude, normobaric hypoxia has been considered as a method of weight loss in obese individuals. With this regard, the aim of the present study was to determine the effect of hypoxia per se on metabolism in men with excess weight. Eight men living with excess weight (125.0 ± 17.7 kg; 30.5 ± 11.1 years...
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Background/objectives Intermittent energy restriction (IER) may overcome poor long-term adherence with continuous energy restriction (CER), for weight reduction. We compared the effects of IER with CER for fasting and postprandial metabolism and appetite in metabolically healthy participants, in whom excess weight would not confound intrinsic metab...
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This study was performed to evaluate the profile of overweight individuals with pre-diabetes enrolled in PREVIEW who were unable to achieve a body weight loss of ≥8% of the baseline value in response to a 2-month low-energy diet (LED). Their baseline profile reflected potential stress-related vulnerability that predicted a reduced response of body...
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Background: Individuals with pre-diabetes are commonly overweight and benefit from dietary and physical activity strategies aimed at decreasing body weight and hyperglycemia. Early insulin resistance can be estimated via the triglyceride glucose index {TyG = Ln [TG (mg/dl) × fasting plasma glucose (FPG) (mg/dl)/2]} and the hypertriglyceridemic-high...
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Plant-based diets are recommended by dietary guidelines. This secondary analysis aimed to assess longitudinal associations of an overall plant-based diet and specific plant foods with weight-loss maintenance and cardiometabolic risk factors. Longitudinal data on 710 participants (aged 26–70 years) with overweight or obesity and pre-diabetes from th...
Article
Background Evidence is emerging that inter-daily meal pattern variability potentially impacts on response such as thermic effect of food (TEF), macronutrient metabolism and appetite. Objectives To investigate the effect of irregular meal pattern on TEF, glucose, insulin, lipid profile and appetite regulation in females with overweight or obesity a...
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Background Observed associations of high-protein diets with changes in insulin resistance are inconclusive. Objectives We aimed to assess associations of changes in both reported and estimated protein (PRep; PEst) and energy intake (EIRep; EIEst) with changes in HOMA-IR, glycated hemoglobin (HbA1c), and BMI (in kg/m2), in 1822 decreasing to 833 ad...
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To evaluate the individual responses in skeletal muscle outcomes following bed rest, data from three studies (21-day PlanHab; 10-day FemHab and LunHab) were combined. Subjects (n=35) participated in three cross-over campaigns within each study: normoxic and hypoxic bed rest, and hypoxic ambulation (used as control). Individual variability (SDIR) wa...
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Background: Previous studies have shown an increase in hunger during weight-loss maintenance (WLM) after diet-induced weight loss. Whether a combination of a higher protein, lower glycemic index (GI) diet and physical activity (PA) can counteract this change remains unclear. Aim: To compare the long-term effects of two diets [high protein (HP)-low...
Article
Objective: To examine longitudinal and dose-dependent associations of dietary glycemic index (GI), glycemic load (GL), and fiber with body weight and glycemic status during 3-year weight loss maintenance (WLM) in adults at high risk of type 2 diabetes. Research design and methods: In this secondary analysis we used pooled data from the PREVentio...
Conference Paper
Background: Prevalence of obesity has reached a global pandemic with high incidence of Type 2 Diabetes (T2D). New Zealand is no exception with 65% overweight including 32% obese, and T2D incidence of 10.9%. The risk of T2D in Maori, Pacific and Asian is double that of Caucasians. Aims: PREVIEW-NZ investigated the effect of an 8-week low energy diet...
Article
Objective: Impaired awareness of hypoglycemia (IAH) in type 1 diabetes (T1D) is a major risk factor for severe hypoglycemia (SH) and is associated with atypical responses to hypoglycemia in brain regions involved in arousal, decision making, and memory. Whether restoration of hypoglycemia awareness alters these responses is unknown. We sought to i...
Article
Previous evidence confirms a relationship between the timing of food intake and weight loss in humans. We aimed to evaluate the effect of late versus early evening meal consumption on weight loss and cardio-metabolic risk factors in women during a weight loss program. 82 Healthy women [BMI = 27- 35 kg/m ² ; age= 18-45 y] were randomly assigned into...
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Aim: To compare the impact of two long-term weight-maintenance diets, a high protein (HP) and low glycaemic index (GI) diet versus a moderate protein (MP) and moderate GI diet, combined with either high intensity (HI) or moderate intensity physical activity (PA), on the incidence of type 2 diabetes (T2D) after rapid weight loss. Materials and met...
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Weight regain after weight loss is a main challenge in obesity management. Cognitive behavioral therapy (CBT) has been introduced as an option for achieving weight loss but not tested for weight maintenance. The aim of this study was to evaluate the effects of CBT on weight maintenance after successful weight loss. Female adults [n = 113, BMI = 23–...
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Aims/hypothesis: We examined the effect of a standardised sympathetic stimulus, incremental adrenaline (epinephrine) infusion on cardiac repolarisation in individuals with type 1 diabetes with normal autonomic function, subclinical autonomic neuropathy and established autonomic neuropathy. Methods: Ten individuals with normal autonomic function...
Article
Background and aims: Computed tomography (CT)-based measurement of skeletal muscle cross-sectional area (CSA) and Hounsfield unit (HU) radiodensity are used to assess the presence of sarcopenia and myosteatosis, respectively. The validated CT-based technique involves analysis of skeletal muscle at the third lumbar vertebral (L3) level. Recently th...
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Background & aims: Blood volume expanding properties of colloids are superior to crystalloids. In addition to oncotic/osmotic properties, the electrolyte composition of infusions may have important effects on visceral perfusion, with infusions containing supraphysiological chloride causing hyperchloremic acidosis and decreased renal blood flow. In...
Article
Objective: Impaired awareness of hypoglycemia (IAH) affects one-quarter of adults with type 1 diabetes and significantly increases the risk of severe hypoglycemia. Differences in regional brain responses to hypoglycemia may contribute to the susceptibility of this group to problematic hypoglycemia. This study investigated brain responses to hypogl...
Article
Whole grain cereal breakfast consumption has been associated with beneficial effects on glucose and insulin metabolism as well as satiety. Pearl millet is a popular ancient grain variety that can be grown in hot, dry regions. However, little is known about its health effects. This study investigated the effect of a pearl millet porridge (PMP) compa...
Article
Brain responses to low plasma glucose may be key to understanding the behaviors that prevent severe hypoglycemia in type 1 diabetes. This study investigated the impact of long duration, hypoglycemia aware type 1 diabetes on cerebral blood flow responses to hypoglycemia. Three-dimensional pseudo-continuous arterial spin labeling magnetic resonance i...
Article
Objective This study aimed to evaluate the effect of different daily physical activity (PA) frequencies, while maintaining the same daily volume of PA, on weight loss, carbohydrate metabolism, and lipid metabolism in women with overweight or obesity throughout a 24‐week intervention. Methods During their weight‐loss plan, 65 women (BMI = 27‐35 kg/...
Article
Objective: Hypoglycemia has been linked to persistent increases in cardiovascular (CV) mortality in type 2 diabetes after the event. Our aim was to examine acute and downstream effects of hypoglycemia on markers of thrombosis risk and inflammation in type 2 diabetes. Research design and methods: Twelve individuals with type 2 diabetes with no hi...
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Glycaemic, gastrointestinal, hormonal and appetite responses to pearl millet and oats porridge breakfast: a randomized, crossover trial - Volume 77 Issue OCE4 - Jaber Alyami, Ella Whitehouse, Susan E. Pritchard, Caroline L. Hoad, Khaled Heissam, Elaine Blackshaw, Sally Cordon, Robin C. Spiller, Penny A. Gowland, Ian A. Macdonald, Guruprasad P. Aith...
Article
Context Hypoglycemia is emerging as a risk for cardiovascular events in diabetes. We hypothesized that hypoglycemia activates the innate immune system, which is known to increase cardiovascular risk. Objective To determine whether hypoglycemia modifies subsequent innate immune system responses. Design and Setting Single-blinded, prospective study...
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Objectives: The analysis of body composition from computed tomography (CT) imaging has become widespread. However, the methodology used is far from established. Two main software packages are commonly used for body composition analysis, with results used interchangeably. However, the equivalence of these has not been well established. The aim of t...
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Aims/hypothesis: Impaired awareness of hypoglycaemia (IAH) in type 1 diabetes increases the risk of severe hypoglycaemia sixfold and can be resistant to intervention. We explored the impact of IAH on central responses to hypoglycaemia to investigate the mechanisms underlying barriers to therapeutic intervention. Methods: We conducted [15O]water...
Conference Paper
Human 13C MRS has recently shown its further potential in understanding neurological disorders. In the field of schizophrenia, 1H MRS has been applied with findings of abnormal concentrations of glutamate ﴾Glu﴿ and glutamine ﴾Gln﴿ in anterior cingulate cortex ﴾ACC﴿. It is therefore of interest to measure glutamate metabolism with 13C MRS in this br...
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Purpose: This study examined the feasibility of sprint interval exercise training (SIT) for men with non-alcoholic fatty liver disease (NAFLD) and its effects on intrahepatic triglyceride (IHTG), insulin sensitivity (hepatic and peripheral), visceral (VAT) and subcutaneous adipose tissue (ScAT). Methods: Nine men with NAFLD (age 41±8 years; BMI 31....
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Background: Beneficial effects of replacing diet beverages (DBs) with water on weight loss, during a 24-week hypoenergetic diet were previously observed. However, it is not known whether this difference is sustained during a subsequent 12-month weight maintenance period. Objective: To evaluate effects of replacing DBs with water on body weight mai...
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Background & aims: The aims of this study were to identify whether differences in distribution of adipose tissue and skeletal muscle in obese and non-obese individuals contribute to the magnitude of the postoperative inflammatory response and insulin resistance, with and without preoperative treatment with carbohydrate drinks. Methods: Thirty-tw...
Article
Cereal grain based porridges are commonly consumed throughout the world. Whilst some data are available for varieties that are popular in the Western world such as oats and rye, other ‘ancient’ grains used in the East and in Africa such as millets are thought to have beneficial health effects, such as a suppression of post prandial hunger and circu...
Article
Objective The aim of this study was to compare the accuracy of measurements of body composition made using dual x-ray absorptiometry (DXA), analysis of computed tomography (CT) scans at the L3 vertebral level, and bioelectrical impedance analysis (BIA). Methods DXA, CT, and BIA were performed in 47 patients recruited from two clinical trials inves...
Article
Background: Circulating branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) have been shown to be associated with insulin resistance and diabetes risk. The common rs1440581 T allele in the protein phosphatase Mg2+/Mn2+ dependent 1K (PPM1K) gene has been related to elevated BCAA concentrations and risk of type 2 diabetes.Objective: In...
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This study investigated how acute restoration of normoglycaemia affected energy metabolism during exercise in nonobese patients with type 2 diabetes. Six subjects (mean ± SEM) aged 56.2 ± 2.7 years, with a BMI of 24.5 ± 1.5 kg/m ² and a VO 2 peak of 28.7 ml/kg/min, attended the lab on two randomised occasions for a four-hour resting infusion of ins...
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Introduction: Sprint interval training (SIT) is a novel form of exercise (high intensity, short duration) which improves IS in healthy, overweight adults despite a total exercise volume much lower than current guidelines. This study investigated the effects of SIT on hepatic and peripheral IS, and IHTG, in men with NAFLD. Methods: 9 overweight/obe...
Article
Objectives The aim of this study was to determine, from the methodologic standpoint, the effect of the presence or absence of intravenous contrast on body composition variables obtained by analysis of computed tomography (CT) images. Methods Triphasic abdominal (noncontrast, arterial phase, and portovenous phase contrast) CT scans from 111 patient...
Article
Short-term very low energy diets (VLED) are used in clinical practice prior to bariatric surgery, however, regimens vary and outcomes for a short intervention are unclear. We examined the effect of two VLEDs; a food-based diet (FD) and meal replacement plan (MRP) (LighterLife) over two weeks in a randomised controlled trial (RCT). We collected clin...
Poster
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Title Child weight status influences the improvement in insulin sensitivity following a short-term energy restriction in severely obese patients. Introduction Ectopic lipid accumulation is a common factor underlying non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes (DM). Adipose tissue capacity that is fixed in adolescence and overwhelm...
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Background: The effect of intensity and duration of physical activity (PA) on weight loss has been well described. However, the effect of the frequency of weekly PA on weight loss is still unknown. Objective: The purpose of this study was to evaluate the effect of the frequency of weekly PA sessions while maintaining the same total activity time...
Article
Background & aims: Patients with pancreatic cancer have a poor prognosis, are often cachectic, and frequently demonstrate features of systemic inflammation, which may contribute to the phenomenon of myosteatosis. Analysis of body composition from CT scans has been used to study sarcopenia and its association with prognosis in a number of types of c...
Article
Aims: To compare the effect of replacing diet beverages (DBs) with water or continuing to drink DBs in patients with type 2 diabetes during a 24-week weight loss program. The primary endpoint was the effect of intervention on weight over a 24-week period. The main secondary endpoints included anthropometric measurement and glucose and fat metaboli...
Article
Aim: To investigate the acute and longer-term effects of low (LGI) versus high glycaemic index (HGI) diets on hepatic fat and glycogen accumulation and related blood measures in healthy volunteers. Methods: Eight healthy men (age 20.1 � 0.4 years, body mass index 23.0 � 0.9 kg/m2) attended a test day before and after a 7-day macronutrient- and ener...
Poster
Full-text available
Background: Ectopic lipid accumulation is a common factor underlying non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes (DM). Adipose tissue capacity, fixed in adolescence and overwhelmed in obesity in adulthood, is one explanation for this deposition. Acute energy restriction reduces lipid deposits in the liver and reverses DM; we aimed...
Poster
Background: Ectopic lipid accumulation is a common factor underlying non-alcoholic fatty liver disease (NAFLD) and Type 2 diabetes (DM). Adipose tissue capacity, fixed in adolescence and overwhelmed in obesity in adulthood, is one explanation for this deposition. Acute energy restriction reduces lipid deposits in the liver and reverses DM; we aimed...
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Full-text available
Background: The association between the time of nutrient intake and health has been described in a few studies. To our knowledge, no study has evaluated the relation between high energy intakes at lunch compared with at dinner on weight loss in overweight and obese subjects. Objective: We compared the effect of high energy intake at lunch with t...
Article
Aims: To investigate the acute and longer term effects of low (LGI) v high (HGI) glycaemic index diets on hepatic fat and glycogen accumulation and related blood measures in healthy volunteers. Methods: Eight healthy males (age = 20.1 ± 0.4y, BMI=23.0 ± 0.9 kg/m2) attended a test day before and after a 7-day macronutrient and energy matched HGI...
Article
Environmental hypoxia and inactivity have both been shown to modulate appetite. To elucidate the independent and combined effects of hypoxia and bed rest-induced inactivity on appetite-related hormones and subjective appetite, eleven healthy, non-obese males underwent three experimental interventions in a cross-over and randomized fashion: 1) Hypox...
Article
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Bone losses are common as a consequence of unloading and also in patients with chronic obstructive pulmonary disease (COPD). Although hypoxia has been implicated as an important factor to drive bone loss, its interaction with unloading remains unresolved. The objective therefore was to assess whether human bone loss caused by unloading could be agg...