https://docs.google.com/spreadsheets/d/1jm8n1kyEx2qDJxFXGne62bzZmCwneKMU/edit#gid=1657087338
Throughout human evolution, several significant dietary shifts have occurred, driven by cultural innovation, changes in habitat, and ecological factors. These shifts include the introduction of meat consumption, the development of cooking techniques, and adaptations related to the domestication of plants and animals. Studying the genetic markers of adaptation to these dietary changes in extant primates, including humans, provides insight into our evolutionary history and the genetic basis of common metabolic diseases in contemporary human populations.
This review offers a concise overview of these pivotal dietary transformations during hominin evolution and discusses the methodologies employed to detect signs of natural selection in sequence variation. We further explore the findings from research identifying key genetic loci responsible for dietary adaptations and highlight the prospects for future research in this field.
Factors Influencing Total Energy Requirements
Various factors affect energy needs, including age, sex, body size, climate, the activity of endocrine glands, health status, and altered physiological states.
Age: Energy requirements are high during infancy due to a higher basal metabolic rate (BMR) and gradually decline after early adulthood. The peak BMR occurs between ages one and two, followed by a steady decline through to adulthood.
Sex: Males generally have a higher BMR than females due to having more muscle and glandular tissue, which is metabolically active, whereas females have more adipose tissue, which is less metabolically active.
Body Size: Larger body size necessitates higher energy due to more muscle and glandular tissue to maintain. Heat loss through the skin, proportional to surface area, also affects BMR, with taller, thinner individuals having higher BMR than shorter, heavier individuals.
Climate: BMR is typically lower in tropical climates than in temperate ones, with energy costs for physical activity increasing in colder temperatures.
Endocrine Glands: The thyroid gland significantly influences energy needs; an overactive thyroid increases the BMR, while an underactive thyroid reduces it.
Health Status: Illness, particularly those that elevate body temperature or involve malnutrition, can alter BMR, thus affecting energy needs.
Altered Physiological States: Energy requirements are heightened during pregnancy and lactation due to increased BMR needed for foetal growth and milk production.
Effect of Food: Digestion, absorption, and metabolism of food raise metabolic rate, known as the specific dynamic action of food, with proteins causing a significant increase.
Extent of Physical Activity: Physical activity raises energy expenditure beyond basal levels, with different types of work demanding varying amounts of energy, from sedentary tasks to heavy manual labour.
Conclusion
Nutrition plays a critical role in growth, health, and well-being. Adequate nutrition can prevent future illnesses and enhance the quality and length of life. Assessing nutritional status can be done through various methods, including physical measurements, dietary intake analysis, and biochemical tests. Proper nutrition is crucial for health and productivity, whereas undernutrition can have severe consequences on intellectual and physical capacities, perpetuating poverty.
