Grant M. Tinsley

Grant M. Tinsley
Texas Tech University | TTU · Department of Kinesiology & Sport Management

Ph.D.

About

127
Publications
64,929
Reads
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2,524
Citations
Citations since 2016
117 Research Items
2526 Citations
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Introduction
I am an Associate Professor at Texas Tech University and the Director of the Energy Balance & Body Composition Laboratory. My major research interests are: 1) The validity and reliability of body composition assessment techniques 2) The efficacy and effectiveness of sports nutrition strategies, including dietary supplementation 3) The effects of intermittent fasting in active populations
Additional affiliations
September 2021 - October 2021
Texas Tech University
Position
  • Professor (Associate)
Education
August 2013 - August 2016
Baylor University
Field of study
  • Kinesiology & Exercise Nutrition
August 2012 - August 2013
Colorado State University
Field of study
  • Biomedical Sciences
August 2008 - August 2012
Oklahoma State University - Stillwater
Field of study
  • Nutritional Sciences

Publications

Publications (127)
Article
Full-text available
Background: A very limited amount of research has examined intermittent fasting (IF) programs, such as time-restricted feeding (TRF), in active populations. Objective: Our objective was to examine the effects of TRF, with or without β-hydroxy β-methylbutyrate (HMB) supplementation, during resistance training (RT). Methods: This study employed...
Article
Full-text available
Background Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the...
Article
Full-text available
A randomized controlled trial was conducted to examine eight weeks of resistance training (RT) with and without time-restricted feeding (TRF) in order to assess nutrient intake and changes in body composition and muscular strength in young recreationally active males. The TRF programme consisted of consuming all calories within a four-hour period o...
Article
Intermittent fasting is a broad term that encompasses a variety of programs that manipulate the timing of eating occasions by utilizing short-term fasts in order to improve body composition and overall health. This review examines studies conducted on intermittent fasting programs to determine if they are effective at improving body composition and...
Article
Purpose: Simple body composition models, such as two-compartment models, employ assumptions which may be violated in specific athletic populations (e.g. the constancy of fat-free mass density [DFFM] and hydration [TBW:FFM]). The present analysis examined FFM characteristics of muscular physique athletes. Methods: Twenty-six athletes (16 M: 94.5±...
Article
The purpose of this investigation was to expand upon the limited existing research examining the test-retest reliability, cross-sectional validity, and longitudinal validity of a sample of bioelectrical impedance analysis (BIA) devices as compared to a laboratory four-compartment (4C) model. Seventy-three healthy participants aged 19-50 were assess...
Article
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Myostatin, a secreted growth factor belonging to the transforming growth factor β (TGF-β) family, performs a role in hindering muscle growth by inhibiting protein kinase B (Akt) phos-phorylation and the associated activation of hypertrophy pathways (e.g., IGF-1/PI3K/Akt/mTOR pathway). In addition to pharmacological agents, some supplements and nutr...
Article
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This study aimed to (i) characterise the body composition of professional and semi- professional male futsal players, (ii) assess the validity of commonly used equations to estimate FM%, (iii) develop and cross-validate a futsal-specific FM% prediction equation. In a cross-sectional design, 78 adult male futsal players were assessed for body mass,...
Article
Assessments of visceral adipose tissue (VAT) are critical in preventing metabolic disorders; however, there are limited measurement methods that are accurate and accessible for VAT. The purpose of this cross-sectional study was to evaluate the association between VAT estimates from consumer grade devices and traditional anthropometrics and VAT and...
Article
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New equations were derived to predict the density of the body (DB) by hydrostatic weighing with the head above water (HWHAW). Hydrostatic weighing with the head below water (HWHBW) was the criterion for DB measurement in 90 subjects (44 M, 46 F). Head volume by immersion (HVIMM) was determined by subtracting the mass in water with the head below wa...
Article
Background : Emerging studies have employed time-restricted feeding (TRF) and a low-sugar diet alone in the management of nonalcoholic fatty liver disease (NAFLD), but their combination has not been tested. Objectives : To investigate the effects of TRF combined with a low-sugar diet on NAFLD parameters, cardiometabolic and inflammatory biomarkers...
Article
Background & Aims Visual body composition (VBC) estimates produced from smartphone-based artificial intelligence represent a user-friendly and convenient way to automate body composition remotely and without the inherent geographical and monetary restrictions of other body composition methods. However, there are limited studies that have assessed t...
Article
Full-text available
Introduction: Nutrition programs can effectively influence physiological systems both at rest and in response to exercise. In the present study, the effect of time-restricted eating (TRE) on two steroid hormones, namely testosterone and cortisol and the ratio of testosterone to cortisol, at rest and in response to a session of exhaustive endurance...
Article
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Multivitamin/mineral (MVM) supplements are one of the most popular dietary supplement categories. The purpose of this analysis was to determine if a novel liposomal delivery mechanism improves mineral absorption from an MVM product. In a randomized crossover trial, 25 healthy participants (12 females, 13 males) completed two testing sessions in whi...
Article
Historically, fat mass has been considered to have significant influence on human body energy homeostasis through its indirect relationship with appetite control. However, over the last decade there has been a surge of evidence supporting the potential role of fat-free mass (FFM) in appetite control, and thus the regulatory involvement of FFM in ap...
Article
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The assessment of body composition over a competitive season provides valuable information that can help sports professionals to evaluate the efficacy of training and nutritional strategies, as well as monitoring athletes’ health status. The purpose of this study was to examine the association of changes in body composition and hydration status wit...
Article
Full-text available
Background: The purpose of this case study was to implement an evidence-based dietary approach to peaking for a bodybuilding competition and monitor its impact on body composition, muscle thickness (MT), intra-to-extra-cellular fluid shifts, subcutaneous thickness (ST), and hydration status. Secondarily, to document any adverse events of this peak...
Preprint
The aim of this study was to assess the precision and agreement of a visual body composition (VBC) application using a 4-compartment (4C) model criterion. Body composition estimations were collected from 102 participants using methods required for a 4C model and a VBC application using two different smartphone types. Intraclass correlation coeffici...
Article
This exploratory study investigated the effects of early vs . delayed time-restricted eating (TRE) plus caloric restriction (CR) on body weight, body composition, and cardiometabolic parameters in adults with overweight and obesity. Adults (20 to 40 years) were randomized to 1 of 3 groups for 8 weeks: early TRE (eTRE; 8:00-16:00) plus CR, delayed T...
Article
Full-text available
This study evaluated the influence of acute water ingestion and maintaining an upright posture on raw bioimpedance and subsequent estimates of body fluids and composition. Twenty healthy adults participated in a randomized crossover study. In both conditions, an overnight food and fluid fast was followed by an initial multi-frequency bioimpedance a...
Article
Full-text available
Background: There is substantial consumer and practitioner interest in an emerging supplement class known as multi-ingredient pre-workout supplements (MIPS), largely due to their prevalence in resistance training communities as well as research findings demonstrating the ergogenic impact of caffeine on muscular performance. However, limited resear...
Article
Intermittent fasting (IF) is a dietary strategy that involves alternating periods of abstention from calorie consumption with periods of ad libitum food intake. There is significant interest in the body of literature describing longitudinal adaptations to IF. Less attention has been given to the acute physiological responses that occur during the f...
Article
Few investigations have evaluated the validity of current body composition technology among racially and ethnically diverse populations. This study assessed the validity of common body composition methods in a multi-ethnic sample stratified by race and ethnicity. 110 individuals (55% female, age: 26.5±6.9 yrs) identifying as Asian, African American...
Article
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Chronobiology plays a crucial role in modulating many physiological systems in which there is nutritional synergism with meal timing. Given that intermitting fasting (IF) has grown as a flexible dietary method consisting of delayed or early eating windows, this scoping review addresses the effects of IF protocols on metabolism as they relate to cli...
Article
Previous studies evaluating the effects of betaine supplementation on body composition offer contradictory findings. This systematic review and meta-analysis assessed the effects of betaine supplementation on body composition indices (body mass [BM], body mass index [BMI], body fat percentage [BFP], fat mass [FM], fat-free mass [FFM]), and dietary...
Article
Harty, PS, Friedl, KE, Nindl, BC, Harry, JR, Vellers, HL, and Tinsley, GM. Military body composition standards and physical performance: historical perspectives and future directions. J Strength Cond Res XX(X): 000-000, 2021-US military physique and body composition standards have been formally used for more than 100 years. These metrics promote ap...
Article
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The present study examined cross-sectional and longitudinal relationships between total and segmental subcutaneous tissue thicknesses from ultrasonography (US) and total and segmental fat mass (FM) estimates from dual-energy X-ray absorptiometry (DXA). Traditional US FM estimates were also examined. Twenty resistance-trained males (mean ± SD; age:...
Article
Full-text available
Tracking changes in body composition may provide key information about the effectiveness of training programs for athletes. This study reports on the agreement between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) for tracking body composition changes during a seven-week offseason training program in 29 NCAA coll...
Article
The present study reports the validity of multiple assessment methods for tracking changes in body composition over time and quantifies the influence of unstandardized pre-assessment procedures. Resistance-trained males underwent 6 weeks of structured resistance training alongside a hypercaloric diet, with four total body composition evaluations. P...
Article
Introduction: Recently, a modified intermittent fasting protocol was demonstrated to be able to maintain muscle mass and strength, decrease fat mass and improve some inflammation and cardiovascular risk factors in healthy resistance-trained males after 2 months. The present study sought to investigate the long-term effects on these parameters. Me...
Article
Full-text available
Background Due to inherent errors involved in the transformation of raw bioelectrical variables to body fluids or composition estimates, the sole use of resistance (R), reactance (Xc), and phase angle (φ) has been advocated when quantifying longitudinal changes. The aim of this investigation was to assess the ability of four bioimpedance analyzers...
Article
Rodriguez, C, Harty, PS, Stratton, MT, Siedler, MR, Smith, RW, Johnson, BA, Dellinger, JR, Williams, AD, White, SJ, Benavides, ML, and Tinsley, GM. Comparison of indirect calorimetry and common prediction equations for evaluating changes in resting metabolic rate induced by resistance training and a hypercaloric diet. J Strength Cond Res 36(11): 30...
Article
This systematic review and meta-analysis evaluated the influence of intermittent fasting (IF) in combination with resistance training (RT) on body composition outcomes. Studies examining IF vs. non-IF diets in individuals performing RT, published up to February 2021, were identified through PubMed, the Cochrane Library, Web of Science, Embase, and...
Article
Dependent variables commonly studied during countermovement vertical jump (CMVJ) tests largely stem from male-only studies despite females' distinct energy storage and reutilisation strategies. This could limit progress among females seeking increased CMVJ performance through targeted changes in certain variables. We explored relationships between...
Article
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Relatively few investigations have reported purposeful overfeeding in resistance-trained adults. This preliminary study examined potential predictors of resistance training (RT) adaptations during a period of purposeful overfeeding and RT. Resistance-trained males (n = 28; n = 21 complet-ers) were assigned to 6 weeks of supervised RT and daily cons...
Article
Controversy regarding the effects of betaine supplementation on cardiovascular markers has persisted for decades. This systematic review and meta-analysis compared the effects of betaine sup-plementation on cardiovascular disease (CVD) markers. Studies examining betaine supplementation on CVD markers published up to February 2021 were identified th...
Article
Multi-compartment body-composition models that divide the body into its multiple constituents are the criterion method for measuring body fat percentage, fat mass, and fat-free mass. However, 2- and 3-compartment body-composition devices such as air displacement plethysmography (ADP), DXA, and bioelectrical impedance devices [bioelectrical impedanc...
Article
ABSTRACT: We evaluated the effects of ketogenic diets (KDs) on body mass (BM), fat mass (FM), fat-free mass (FFM), body mass index (BMI), and body fat percentage (BFP) compared to non-KDs in individuals performing resistance training (RT). Online electronic databases including PubMed, the Cochrane Library, Web of Science, Embase, SCOPUS, and Ovid w...
Article
To the Editor Lowe et al¹ recently published a randomized clinical trial reporting that extended daily fasting, or time-restricted eating (TRE), does not improve body weight or cardiometabolic risk factors and slightly decreases appendicular lean mass, a surrogate for muscle mass. This important study is the largest published trial of TRE and sugge...
Article
Objective: Bioimpedance devices are commonly used to assess health parameters and track changes in body composition. However, the cross-sectional agreement between different devices has not been conclusively established. Thus, the objective of this investigation was to examine the agreement between raw bioelectrical variables (resistance, reactanc...
Article
Full-text available
The fate of dietary protein in the gut is determined by microbial and host digestion and utilization. Fermentation of proteins generates bioactive molecules that have wide-ranging health effects on the host. The type of protein can affect amino acid absorption, with animal proteins generally being more efficiently absorbed compared with plant prote...
Article
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Background Although there is substantial interest in intermittent fasting as a dietary approach in active individuals, information regarding its effects in elite endurance athletes is currently unavailable. The present parallel randomized trial investigated the effects of a particular intermittent fasting approach, called time-restricted eating (TR...
Article
Full-text available
Little is known about the optimal time to consume caffeine prior to exercise to maximize the ergogenic benefits of the substance. Purpose: To determine the optimal pre-exercise time interval to consume caffeine to improve lower-body muscular performance. A secondary aim was to identify the presence of any sex differences in responses to timed caffe...
Article
Background & aims Fasting and energy-restricted diets have been evaluated in several studies as a means of improving cardiometabolic biomarkers related to body fat loss. However, further investigation is required to understand potential alterations of leptin and adiponectin concentrations. Thus, we performed a systematic review and meta-analysis to...
Article
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A scientific interest has emerged to identify pharmaceutical and nutritional strategies in the clinical management of coronavirus disease 2019 (COVID-19). The purpose of this narrative review is to critically assess and discuss pharmaconutrition strategies that, secondary to accepted treatment methods, could be candidates in the current context of...
Article
"Eat breakfast like a king, lunch like a prince and dinner like a pauper" (Adelle Davis, 1904-1974) is a concept that appears to align with some contemporary evidence concerning the appropriate proportioning of daily meals. At the same time, with the popular and scientific dissemination of the concepts of intermittent fasting and time-restricted fe...
Article
This study reports the validity of body fat percentage (BF%) estimates from several commonly employed techniques as compared to a 5-component (5C) model criterion. Healthy adults (n=170) were assessed by dual-energy x-ray absorptiometry (DXA), air displacement plethysmography (ADP), multiple bioimpedance techniques, and optical scanning. Output was...
Article
We carried out a prospective case study in a high-level amateur natural male bodybuilder throughout preparation for 4 competitions and during the ensuing post-contest recovery period. Laboratory testing was conducted monthly over a 1-year period, which included the following assessments: B-mode ultrasound evaluation of muscle thickness (MT), multi-...
Article
Full-text available
Background: Energy drinks are often consumed by the general population, as well as by active individuals seeking to enhance exercise performance and augment training adaptations. However, limited information is available regarding the efficacy of these products. Thus, the purpose of this study was to determine the effects of a commercially availab...
Article
Purpose: The purpose of this study was to assess the agreement of a field-based 3-compartment model (3CFIELD) as compared to a laboratory-based 3-compartment model (3CLAB) for tracking body composition changes over time. Methods: Resistance-trained males completed a supervised nutrition and resistance training intervention. Before and after the...
Article
Background & aims Low-carbohydrate diets (LCD) have gained substantial attention in recent years for their potential in health promotion and treatment of diseases, but they remain controversial in nutrition guidelines and exercise performance. Herein, through a literature review, we discuss the current evidence base by considering management of LCD...
Article
Full-text available
Meal timing may be a critical modulator of health outcomes due to complex interactions between circadian biology, nutrition and human metabolism. As such, approaches that aim to align food consumption with endogenous circadian rhythms are emerging in recent years. Time-restricted eating (TRE) consists of limiting daily nutrient consumption to a per...
Article
Full-text available
Digital anthropometry is increasingly accessible due to commercial availability of three-dimensional optical scanners (3DO). One hundred and seventy-nine participants were assessed by four 3DO systems (FIT3D®, Size Stream®, Styku®, and Naked Labs®) in duplicate, air displacement plethysmography (ADP), and dual-energy x-ray absorptiometry (DXA). Tes...
Article
Common body composition estimation techniques necessitate assumptions of uniform fat-free mass (FFM) characteristics, although variation due to sex, race, and body characteristics may occur. National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2004, during which paired dual-energy X-ray absorptiometry (DXA) and bioimpedance s...
Article
Full-text available
Objectives Concurrent Training (CT) is described as a combination of resistance training (RT) and endurance training (ET) in a periodized program to maximize all aspects of physical performance. To date, effects of CT order on muscular and cardiorespiratory fitness adaptations are controversial. Owing to the age-related decrement in satellite cells...
Article
This systematic review and meta-analysis compared the effects of different rates of weight loss (WL), but equivalent total WL, on body composition and resting metabolic rate (RMR). Studies examining gradual vs. rapid WL on body composition and RMR in participants with overweight/obesity published up to October 2019 were identified through PubMed, t...