Obesity
Conditions
Keywords
OBESITY, WEIGHT LOSS, EATING BEHAVIOR, METABOLIC FLEXIBILITY, BODY COMPOSITION
Brief summary
This interventional study explores the relationship between improvements in metabolic health following weight loss and changes in whole-body fat mass and its distribution. The study focuses on adult men and women with excess body weight undergoing dietary energy restriction over 12 weeks. The primary research question is: Does a greater reduction in fat mass for a given weight loss correlate with more significant improvements in metabolic health?
Detailed description
Obesity is a well-established risk factor for disruptions in metabolic health, which often precede cardiovascular disease and type-2 diabetes. While the precise pathophysiological mechanisms linking obesity to these conditions remain unclear, it is widely acknowledged that an increase in fat mass plays a central role, including the expansion of adipose tissue and the accumulation of lipids in non-adipose tissues. As a result, a primary approach to improving metabolic health is to reduce fat mass through negative energy balance. However, lifestyle changes or pharmacological interventions aimed at inducing a negative energy balance do not exclusively target fat mass and often result in the loss of fat-free mass to varying degrees. Given that higher fat mass, rather than fat-free mass, is more strongly associated with impaired metabolic health, strategies that maximize fat mass loss while preserving fat-free mass may offer more significant benefits for metabolic health. Surprisingly, there is a lack of evidence to support this hypothesis. To address this gap, it will be evaluated the relationship between changes in metabolic health and body composition, independent of overall weight loss, in individuals with overweight or obesity undergoing dietary energy restriction. It is hypothesized that greater fat mass reduction will be linked to more substantial improvements in metabolic health for a given weight loss.
Interventions
OTHERBody Weight Loss
Individuals will be prescribed a hypocaloric diet (1300 kcal/d). Individuals will receive a booklet detailing the type of meals and foods to be consumed in each mealtime. A dietitian will explain how to enhance dietary compliance. Every two weeks, body weight, vital signs, and adverse events will be monitored. In addition, food recalls will be conducted in order to optimize dietary energy restriction compliance. During weight maintenance, energy intake will be adjusted to energy requirements to maintain weight stability (±2.5 kg) for at least 3 weeks. During weight loss and maintenance, participants will be instructed to maintain their customary physical activity.
Sponsors
Jose Galgani
Agencia Nacional de Investigación y Desarrollo
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
30 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
* males or females * 30-55 y old * physically inactive (\<600 MET´min/wk of self-reported moderate-vigorous physical activity * stable body weight for at least the past 6 months (±2 kg) * healthy according to medical history and routine hematology and biochemistry.
Exclusion criteria
* Individuals with physiological (pregnancy, lactation) or pathological (under drug therapy for and/or having cardiovascular, liver, kidney, thyroid diseases) * conditions affecting energy metabolism or eating behavior * Subjects having low-fat (\<20% energy) or low-carbohydrate (\<45% energy) diets * Smokers and alcohol abusers
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fasting serum triglyceride concentration | From enrollment to the end of weight maintenance period at 15-20 weeks | In overnight fasted individuals, a blood sample will be drawn. Serum will be isolated and stored at -80C until assessment. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| HOMA-IR | From enrollment to the end of weight maintenance period at 15-20 weeks. | In overnight fasted individuals, a blood sample will be drawn for glucose and insulin assessment. HOMA-IR will be calculated using this formula: (glucose, mM \* insulin, uU/mL)/22.5. Serum/Plasma will be isolated and stored at -80C until assessment. |
Countries
Chile
Outcome results
None listed