How can we assess "thrifty" and "spendthrift" phenotypes?

Area of Science:

• Metabolic studies
• Human physiology
• Obesity research

Background:

• Significant inter-individual variability exists in body weight changes, not fully explained by energy intake or physical activity.
• This variability is largely attributed to differences in individual energy metabolism.
• Understanding metabolic phenotypes is key to addressing obesity and weight management challenges.

Approach:

• This review summarizes methods to identify individual metabolic phenotypes (thrifty vs. spendthrift).
• Key challenges include short-term fasting, protein-imbalanced overfeeding, and mild cold exposure.
• Whole-room indirect calorimetry is used to quantify metabolic thriftiness during these challenges.

Key Points:

• The energy expenditure response during prolonged fasting is the most accurate measure of metabolic thriftiness.
• Dietary and environmental challenges reveal individual differences in metabolic slowing.
• Alternative methods, like hormonal responses to meals, are being explored for clinical settings.

Conclusions:

• Metabolic thriftiness, assessed through controlled challenges, quantifies susceptibility to weight gain and resistance to weight loss.
• Identifying individual metabolic phenotypes is essential for personalized weight management strategies.
• Further research aims to develop accessible clinical tools for metabolic phenotype assessment.