Yves Schutz

Yves Schutz
University of Lausanne | UNIL · Department of Physiology

MPh, PhD

About

378
Publications
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Publications

Publications (378)
Article
Full-text available
Societal erosion of daily life low-level physical activity has had a great influence on the obesity epidemic. Given that low fat oxidation is also a risk factor for obesity, we investigated, in a repeated measures design, the dynamics of fat oxidation from a resting state to a light-intensity leg cycling exercise (0–50 watts) in inactive, healthy y...
Article
The most appropriate type of diets to maintain or lose body weight over the medium to long term has been a matter of controversy and debates for more than half a century. Both voluntarily and coercive food restriction, resulting in negative energy and macronutrient balance and hence weight loss, have not been designed to be maintained for the long...
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The notion that dieting makes some people fatter has in the past decade gained considerable interest from both epidemiological predictions and biological plausibility. Several large-scale prospective studies have suggested that dieting to lose weight is associated with future weight gain and obesity, with such predictions being stronger and more co...
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Background/objectives: In the tropical island of Mauritius, the rise in obesity has accelerated in the past decades, and could be contributed by low physical activity and increased sedentary behavior. The study objectives were to generate the first dataset of total energy expenditure (TEE), to estimate physical activity in Mauritian children, and...
Article
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It is increasingly recognized that the use of body mass index (BMI) cut-off points for diagnosing obesity and proxy measures for body fatness in a given population needs to take into account the potential impact of ethnicity on the BMI-Fat% relationship in order to avoid adiposity status misclassification. This relationship was studied here in 377...
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Implementation of efficacious dietary interventions to regulate energy balance requires understanding of the determinants of individual response. To date, information regarding individual variability in response to elevated meal protein content is lacking. This study investigates whether sex and/or oral contraceptive pill (OCP) use play a role in t...
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The maximum aerobic metabolic rate can be expressed in multiple metabolically equivalent tasks (MET), i.e., METmax. The purpose was to quantify the error when the conventional (3.5 mL∙kg−1∙min−1) compared to an individualized 1-MET-value is used for calculating METmax and estimating activity energy expenditure (AEE) in endurance-trained athletes (E...
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The first contact for patients with obesity for any medical treatment or other issues is generally with General Practitioners (GPs). Therefore, given the complexity of the disease, continuing GPs’ education on obesity management is essential. This article aims to provide obesity management guidelines specifically tailored to GPs, favouring a practi...
Article
Increasing lifestyle energy expenditure has long been advocated in the prevention and treatment of obesity, as embodied in the ancient prescription of Hippocrates (the ‘father of modern medicine’) that people with obesity should eat less and exercise more. However, the long‐term outcome of exercise alone or in combination with dieting in obesity ma...
Conference Paper
Background: There is a need to establishthe range of proteinintake that would constitute an acceptable ‘high-protein’ diet for weight management, particularly towards the prevention of obesity and weight relapse. The pilot study described here aimed to (i) define the dose–response relationship between meal protein content and postprandial thermogen...
Conference Paper
Introduction: Obesity is more prevalent in women than men worldwide, with the rising prevalence amongst young women of child-bearing age of particular concern. Whilst the underlying mechanism for this gender disparity is largely unknown, oral contraceptive pill (OCP) use may be a factor that contributes to the alteration in energy balance in young...
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Collateral fattening refers to the process whereby excess fat is deposited as a result of the body's attempt to counter a deficit in lean mass through overeating. Its demonstration and significance to weight regulation and obesity can be traced to work on energy budget strategies in growing mammals and birds, and to men recovering from experimental...
Article
Recent body composition studies on the island of Mauritius in young adults belonging to the two main ethnicities—Indians (South Asian descent) and Creoles (African/Malagasy descent)—have shown gender-specific ethnic differences in their body mass index (BMI)-Fat% relationships. We investigated here whether potential gender and ethnic differences in...
Article
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Objective: There is much interest in the role of dietary protein for weight control. However, there remains a need to characterize individual determinants of the thermogenic effects of protein. This study aimed to investigate the influence of menstrual cycle phase and the combined, monophasic oral contraceptive pill on the thermogenic response to...
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Background There is increasing interest in the use of pill-sized ingestible capsule telemetric sensors for assessing core body temperature (Tc) as a potential indicator of variability in metabolic efficiency and thrifty metabolic traits. The aim of this study was to investigate the feasibility and accuracy of measuring Tc using the CorTemp® system....
Conference Paper
Introduction: Successful approaches to weight control should elicit effects on both sides of the energy balance equation, i.e., energy intake and expenditure. For this reason there has been much interest in the role of dietary protein, which has been demonstrated to favourably affect satiety, thermogenesis, body weight and body composition. However...
Article
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Standardized approaches to assess human energy expenditure (EE) are well defined at rest and at moderate to high‐intensity exercise, but not at light intensity physical activities energetically comparable with those of daily life (i.e., 1.5–4 times the resting EE, i.e., 1.5–4 METs). Our aim was to validate a graded exercise test for assessing the e...
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Background Endurance athletes perform periodized training in order to prepare for main competitions and maximize performance. However, the coupling between alterations of total energy expenditure (TEE), energy intake, and body composition during different seasonal training phases is unclear. So far, no systematic review has assessed fluctuations in...
Article
Isometric thermogenesis as applied to human energy expenditure refers to heat production resulting from increased muscle tension. While most physical activities consist of both dynamic and static (isometric) muscle actions, the isometric component is very often essential for the optimal performance of dynamic work given its role in coordinating pos...
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While putative feedback signals arising from adipose tissue are commonly assumed to provide the molecular links between the body’s long-term energy requirements and energy intake, the available evidence suggests that the lean body or fat-free mass (FFM) also plays a role in the drive to eat. A distinction must, however, be made between a ‘passive’...
Article
Background and Aims Global estimates of overweight and obesity prevalence are based on the World Health Organisation (WHO) body mass index (BMI) cut-off values of 25 and 30 kg m⁻², respectively. To validate these BMI cut-offs for adiposity in the island population of Mauritius, we assessed the relationship between BMI and measured body fat mass in...
Article
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“Metabolic Equivalent” (MET) represents a standard amount of oxygen consumed by the body under resting conditions, and is defined as 3.5 mL O2/kg × min or ~1 kcal/kg × h. It is used to express the energy cost of physical activity in multiples of MET. However, universal application of the 1-MET standard was questioned in previous studies, because it...
Article
Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investig...
Article
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Background and aim: There is increasing recognition about the importance of enhancing energy expenditure (EE) for weight control through increases in low-intensity physical activities comparable with daily life (1.5-4 METS). Whole-body vibration (WBV) increases EE modestly and could present both a useful adjuvant for obesity management and tool fo...
Article
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Better understanding is needed regarding the effects of exercise alone, without any imposed dietary regimens, as a single tool for body-weight regulation. Thus, we evaluated the effects of an 8-week increase in activity energy expenditure (AEE) on ad libitum energy intake (EI), body mass and composition in healthy participants with baseline physica...
Article
Dieting and exercise are likely to remain the core approaches in the management of obesity in the foreseeable future despite their well-documented failures for achieving long-term weight loss. Explanations for such poor prognosis are centered on patient’s self-regulatory failure and lack of compliance to the prescribed diet or exercise regimen. Whi...
Article
Indirect calorimetry, the measurement of O2 consumption and CO2 production, constitutes an invaluable tool as the most common method for analyzing whole body energy expenditure, and also provides an index of the nature of macronutrient substrate oxidation, namely carbohydrate (CHO) versus fat oxidation. The latter constitutes a key etiological fact...
Article
Whether dieting makes people fatter has been a subject of considerable controversy over the past 30 years. More recent analysis of several prospective studies suggest, however, that it is dieting to lose weight in people who are in the healthy normal range of body weight, rather than in those who are overweight or obese, that most strongly and cons...
Article
Despite the poor prognosis of dieting in obesity management, which often results in repeated attempts at weight loss and hence weight cycling, the prevalence of dieting has increased continuously in the past decades in parallel to the steadily increasing prevalence of obesity. However, dieting and weight cycling are not limited to those who are obe...
Article
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Objective While there is a dose-response relationship between physical activity (PA) and health benefit, little is known about the effectiveness of different PA prescriptions on total daily PA. Aim To test, under real-life conditions and using an objective, non-invasive measurement technique (accelerometry), the effect of prescribing additional ph...
Article
Food intake increases to a varying extent during pregnancy to provide extra energy for the growing fetus. Measuring the respiratory quotient (RQ) during the course of pregnancy (by quantifying O2 consumption and CO2 production with indirect calorimetry) could be potentially useful since it gives an insight into the evolution of the proportion of ca...
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The concept of energy gap(s) is useful for understanding the consequence of a small daily, weekly, or monthly positive energy balance and the inconspicuous shift in weight gain ultimately leading to overweight and obesity. Energy gap is a dynamic concept: an initial positive energy gap incurred via an increase in energy intake (or a decrease in phy...
Article
Abstract The purpose of the present investigation was to examine the relationship between the accumulation of 1000 steps in 10 minutes (1K) and 3000 steps in 30 minutes (3K) with the amount and intensity of daily physical activity. Thirty-three adults (16 males and 17 females, 53 ± 19 years) wore an accelerometer (Lifecorder) for seven consecutive...
Article
Aim: Venice, Italy, provides a unique environment to study physical activity as there are no automobiles, and walking is the most common means of transportation. The purpose of the present investigation was to objectively assess the physical activity (PA) levels of residents in Venice, Italy, using an accelerometer. Methods: Twenty-seven Venetia...
Article
Energy expenditure (EE) during sitting is widely assumed to be higher than that while lying down, but supporting evidence is equivocal. Despite this, resting EE in the sitting position is often used as a proxy for basal metabolic rate. Here we investigate whether EE differs in the comfortable seated position compared to supine (lying) position. EE...
Article
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Limitations of current methods: The assessment of human variability in various compartments of daily energy expenditure (EE) under standardized conditions is well defined at rest [as basal metabolic rate (BMR) and thermic effect of feeding (TEF)], and currently under validation for assessing the energy cost of low-intensity dynamic work. However, b...
Article
Background: Increases in physical activity (PA) are promoted by walking in an outdoor environment. Along with walking speed, slope is a major determinant of exercise intensity, and energy expenditure. The hypothesis was that in free-living conditions, a hilly environment diminishes PA to a greater extent in obese (OB) when compared with control (C...
Article
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Reducing sitting-time may decrease risk of disease and increase life-span. In the search for approaches to reduce sitting-time, research often compares sitting to standing and ambulation, but the energetic cost of standing alone versus sitting is equivocal, with large variation in reported mean values (0% to >20% increase in energy expenditure (EE)...
Article
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Among countries which have undergone a rapid socio-economic and nutrition transition over the past few decades, the Indian Ocean island of Mauritius is among those with the greatest surge in the prevalence of type 2 diabetes and CVD. The aim of the present study was to characterise the BMI and cardiovascular functions of children and adolescents of...
Article
According to Lavoisier, 'Life is combustion'. But to what extent humans adapt to changes in food intake through adaptive thermogenesis - by turning down the rate of heat production during energy deficit (so as to conserve energy) or turning it up during overnutrition (so as to dissipate excess calories) - has been one of the most controversial issu...
Article
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Background: Physical activity (PA) and related energy expenditure (EE) is often assessed by means of a single technique. Because of inherent limitations, single techniques may not allow for an accurate assessment both PA and related EE. The aim of this study was to develop a model to accurately assess common PA types and durations and thus EE in f...
Article
Objective: We investigated to what extent changes in metabolic rate and composition of weight loss explained the less-than-expected weight loss in obese men and women during a diet-plus-exercise intervention. Design: In all, 16 obese men and women (41 ± 9 years; body mass index (BMI) 39 ± 6 kg m(-2)) were investigated in energy balance before, a...
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The prevalence of obesity is rising progressively, even among older age groups. By the year 2030–2035 over 20% of the adult US population and over 25% of the Europeans will be aged 65 years and older. The predicted prevalence of obesity in Americans, 60 years and older was 37% in 2010. The predicted prevalence of obesity in Europe in 2015 varies be...
Article
Background & aims: The objective of this study was to assess the validity of the individually calibrated Actiheart (a combined heart rate and movement sensor device), in pregnant women against indirect calorimetry in a laboratory setting. Methods: Ten healthy pregnant women (aged 32.9 ± 3.2 yrs, pre-pregnancy BMI = 21.0 ± 2.4 kg/m 2, 36.9 ± 2.4 wee...
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Waist circumference (WC) is a key variable to assess in health management as it is a proxy of abdominal fat mass and a surrogate marker of cardiometabolic disease risk, including the metabolic syndrome. Recently, a portable non-contact device calculating WC (ViScan) has been developed, which hence allows the tracking of WC independently of the inte...
Article
We report a novel technique for computing diet-induced thermogenesis using data from 24-h respiration chamber measurements of 76 subjects. Physical activity (PA) was determined using a radar system to assess its duration and an accelerometer to evaluate its intensity. The regression line relating PA and energy expenditure facilitated calculation of...
Article
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Obesity is recognised as a global epidemic and the most prevalent metabolic disease world-wide. Specialised obesity services, however, are not widely available in Europe, and obesity care can vary enormously across European regions. The European Association for the Study of Obesity (EASO, www.easo.org) has developed these criteria to form a pan-Eur...
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The development and maintenance of excess body mass in many children is partly attributable to levels of physical activity that are lower than the recommended 60 minutes/day. Walking is a recommended form of physical activity for obese children, due to its convenience and perceived ease of adoption. Unfortunately, studies that have used objective p...
Article
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Monitoring of posture allocations and activities en-ables accurate estimation of energy expenditure and may aid in obesity prevention and treatment. At present, accurate devices rely on multiple sensors distributed on the body and thus may be too obtrusive for everyday use. This paper presents a novel wearable sensor, which is capable of very accur...
Article
The major processes discussed below are protein turnover (degradation and synthesis), degradation into urea, or conversion into glucose (gluconeogenesis, Figure 1). Daily protein turnover is a dynamic process characterized by a double flux of amino acids: the amino acids released by endogenous (body) protein breakdown can be reutilized and reconver...
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The resting metabolic rate (RMR) varies among pregnant women. The factors responsible for this variability are unknown. This study aimed to assess the influence of the prepregnancy body mass index (BMI) on the RMR during late pregnancy. RMR, height, weight, and total (TEE) and activity (AEE) energy expenditures were measured in 46 healthy women age...
Article
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Dynamic changes in body weight have long been recognized as important indicators of risk for debilitating diseases. While weight loss or impaired growth can lead to muscle wastage, as well as to susceptibility to infections and organ dysfunctions, the development of excess fat predisposes to type 2 diabetes and cardiovascular diseases, with insulin...
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Obesity has progressively become a global epidemic that constitutes one of the biggest current health problems worldwide. Pregnancy is a risk factor for excessive weight gain. Factors that may predict development of obesity in later life mainly include gestational weight gain, pre-pregnancy nutritional status, age, parity and race. Change in lifest...
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When fructose is ingested together with glucose (GLUFRU) during exercise, plasma lactate and exogenous carbohydrate oxidation rates are higher than with glucose alone. The objective was to investigate to what extent GLUFRU increased lactate kinetics and oxidation rate and gluconeogenesis from lactate (GNG(L)) and from fructose (GNG(F)). Seven endur...