Measure:
In Vivo Leptin Sensitivity
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Leptin sensitivity will be evaluated as the ratio between caloric intake during an experimental meal and circulating leptin levels. Participants will receive a standardized breakfast and after 3 hours an ad libitum lunch, with detailed records of consumption, additional food requests, and portion sizes. Hunger and satiety will be measured using a 5-item Visual Analogue Scale (VAS) at multiple time points, recorded in millimeters. Energy and nutrient intake will be assessed using nutritional labels from each food item, and leptin sensitivity will be determined via plasma fasting.
Measure:
Ex Vivo Leptin Sensitivity
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Since direct assessment of leptin sensitivity in the central nervous system is not feasible in humans, peripheral leptin sensitivity ex vivo will be evaluated using Peripheral Blood Mononuclear Cells (PBMCs). PBMCs will be collected from the same individuals before and after the intervention and exposed to recombinant leptin to assess intracellular signalling activation. The primary leptin effector pathway is Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3), though Extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) activation has also been reported among others. The activation of these pathways will be measured using immunoassays such as Enzyme Linked Immunosorbent Assay (ELISA) and Western blot, quantifying the ratio of phosphorylated to total protein levels for each intracellular effector.
Measure:
Insulin Sensitivity and Secretion
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Insulin sensitivity and secretion will be assessed both during fasting and the oral glucose tolerance test (OGTT).
Measure:
Energy Metabolism
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Energy metabolism, including resting metabolic rate and diet-induced thermogenesis, will be measured by indirect calorimetry.
Measure:
Fat Mass (percentage)
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Fat mass will be estimated using bioelectrical impedance analysis and expressed as a percentage of total body weight.
Measure:
Fat Mass (kilograms)
TimeFrame:
At baseline (T0), at the end of the 8-week intervention (T1, end of month 2), and 12 weeks after the intervention (T2, end of month 5) to verify the persistence of effects.
Description:
Fat mass will be estimated using bioelectrical impedance analysis and expressed in kilograms.