Introduction to Nutrition 1.2

Specialists vs Generalists

• Specialists consume a limited number of foods, requiring less neural resources but are limited in their food source, forcing them to forage for longer and over greater areas.

Diet Specialization

• Carnivores: meat-eaters with carnassial shears for crushing.
• Herbivores: consume vegetation, with flat broad molars for chewing, e.g., koalas eating eucalyptus.

Generalists

• Consume a variety of foods, e.g., omnivores like humans, rats, bears, and pigs.
• Possess sensory systems that can identify food properties, including toxins and nutrients.

Sensory Systems

• Exteroceptive senses: vision, smell, taste, and touch provide advance information about foods.
• Interoceptive senses: detect food make-up, including nutrients and toxins.

Toxins

• Many plants and some animals produce toxins.
• Many toxins taste bitter, but some do not (idiosyncratic) and can only be detected after eating, leading to illness.
• Regurgitating can help eliminate toxins.

Generalists and Food Consequences

• Generalists associate foods with consequences, such as feeling better or getting sick, based on exteroceptive sensory information at the time of eating.
• The digestive system identifies and digests a variety of substances, adapting to different foods and their unique requirements.

Digestive System Capabilities

• The digestive system employs different digestive approaches, including enzymes and time trajectories, to process various foods.
• Foods can vary dramatically from meal to meal, necessitating flexible digestive strategies.

Nutrient Diversity and Detection

• Generalists require a variety of nutrients that cannot be found in a single natural source.
• A regulatory system ensures nutrient diversity by detecting deficits and guiding behavior towards needed nutrient sources.

Generalists and Food Consequences

• Generalists associate foods with consequences, such as feeling better or getting sick, based on exteroceptive sensory information at the time of eating.
• The digestive system identifies and digests a variety of substances, adapting to different foods and their unique requirements.

Digestive System Capabilities

• The digestive system employs different digestive approaches, including enzymes and time trajectories, to process various foods.
• Foods can vary dramatically from meal to meal, necessitating flexible digestive strategies.

Nutrient Diversity and Detection

• Generalists require a variety of nutrients that cannot be found in a single natural source.
• A regulatory system ensures nutrient diversity by detecting deficits and guiding behavior towards needed nutrient sources.

Generalists and Food Consequences

• Generalists associate foods with consequences, such as feeling better or getting sick, based on exteroceptive sensory information at the time of eating.
• The digestive system identifies and digests a variety of substances, adapting to different foods and their unique requirements.

Digestive System Capabilities

• The digestive system employs different digestive approaches, including enzymes and time trajectories, to process various foods.
• Foods can vary dramatically from meal to meal, necessitating flexible digestive strategies.

Nutrient Diversity and Detection

• Generalists require a variety of nutrients that cannot be found in a single natural source.
• A regulatory system ensures nutrient diversity by detecting deficits and guiding behavior towards needed nutrient sources.

Characteristics of a Complete Diet

• A complete diet requires an optimal balance of nutrients
• Each nutrient must be present in the correct ratio to the energy content of the diet and to each other
• The nutrients must be in a form that is usable by the animal

Factors Affecting Nutrient Availability

• Food ingredients can have different nutrient compositions
• Water content can vary between food ingredients
• Digestibility of food ingredients can differ

Consequences of Excess Nutrient Intake

• Having too much protein can have negative effects

Measuring Nutrient Absorption

• Digestibility tells you an approximate figure for the amount of nutrients in a feed that can be absorbed from the gut and used by the animal for bodily functions

Characteristics of a Complete Diet

• A complete diet requires an optimal balance of nutrients
• Each nutrient must be present in the correct ratio to the energy content of the diet and to each other
• The nutrients must be in a form that is usable by the animal

Factors Affecting Nutrient Availability

• Food ingredients can have different nutrient compositions
• Water content can vary between food ingredients
• Digestibility of food ingredients can differ

Consequences of Excess Nutrient Intake

• Having too much protein can have negative effects

Measuring Nutrient Absorption

• Digestibility tells you an approximate figure for the amount of nutrients in a feed that can be absorbed from the gut and used by the animal for bodily functions

Characteristics of a Complete Diet

• A complete diet requires an optimal balance of nutrients
• Each nutrient must be present in the correct ratio to the energy content of the diet and to each other
• The nutrients must be in a form that is usable by the animal

Factors Affecting Nutrient Availability

• Food ingredients can have different nutrient compositions
• Water content can vary between food ingredients
• Digestibility of food ingredients can differ

Consequences of Excess Nutrient Intake

• Having too much protein can have negative effects

Measuring Nutrient Absorption

• Digestibility tells you an approximate figure for the amount of nutrients in a feed that can be absorbed from the gut and used by the animal for bodily functions

Body Weight Regulation

• Animals maintain a relatively stable body weight range, not a precise point, due to various influences.
• Body weight is affected by numerous factors, including:
  • Temperature
  • Food availability
  • Food variety
  • Food palatability
  • Stress
  • Physical activity
• Environmental changes can cause temporary fluctuations in body weight, but it often returns to "normal."
• The body regulates weight through:
  • Initiation and frequency of meals
  • Amount eaten during meals

Body Weight Regulation

• Animals maintain a relatively stable body weight range, not a precise point, due to various influences.
• Body weight is affected by numerous factors, including:
  • Temperature
  • Food availability
  • Food variety
  • Food palatability
  • Stress
  • Physical activity
• Environmental changes can cause temporary fluctuations in body weight, but it often returns to "normal."
• The body regulates weight through:
  • Initiation and frequency of meals
  • Amount eaten during meals

Body Weight Regulation

• Animals maintain a relatively stable body weight range, not a precise point, due to various influences.
• Body weight is affected by numerous factors, including:
  • Temperature
  • Food availability
  • Food variety
  • Food palatability
  • Stress
  • Physical activity
• Environmental changes can cause temporary fluctuations in body weight, but it often returns to "normal."
• The body regulates weight through:
  • Initiation and frequency of meals
  • Amount eaten during meals

Animal Maintenance

• An animal is in a state of maintenance when its body composition remains constant, and it does not produce any milk, become pregnant, or perform work.
• During maintenance, the animal's body needs a balance of nutrients, including carbohydrates, protein, fat, minerals, vitamins, and water.
• The energy required for maintenance is the amount needed for a moderately active animal to search for and utilize food daily.
• This energy does not include that required for growth, repair, pregnancy, lactation, or work.
• The energy expended for maintenance is lost as heat from the body.
• Maintenance energy is the energy required to be alive, which includes the energy needed for standing up and foraging to stay alive.

Animal Maintenance

• An animal is in a state of maintenance when its body composition remains constant, and it does not produce any milk, become pregnant, or perform work.
• During maintenance, the animal's body needs a balance of nutrients, including carbohydrates, protein, fat, minerals, vitamins, and water.
• The energy required for maintenance is the amount needed for a moderately active animal to search for and utilize food daily.
• This energy does not include that required for growth, repair, pregnancy, lactation, or work.
• The energy expended for maintenance is lost as heat from the body.
• Maintenance energy is the energy required to be alive, which includes the energy needed for standing up and foraging to stay alive.