Eating2 - Eating Hunger Satiety IS FEEDING BEHAVIOR...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Eating – Hunger & Satiety IS FEEDING BEHAVIOR HOMEOSTATICALLY CONTROLLED? Consider the following diagram. It shows that as hours go by, an organism's energy reserves are used and thus its internal resources or reserves are diminished. As the energy reserves fall, hunger sets in (shown in blue), which is followed by the eating of a meal (shown in green). The energy reserves are restored as the meal is digested and the nutrients are absorbed. Then the process cyclesagain, and again, etc. Do you think this is how your eating is controlled? This seems to correlate largely with what our cognitive experience is, and is what many people's intuitions are for how feeding is regulated. But as we take a closer look at it, you may see that this type of set point theory – in which the animal monitors and attempts to maintain the level of some internal energy reserve –doesn't quite explain why we eat, how much we eat, or why we stop eating. It may not even do a very good job of explaining how our body weight is maintained -- or not maintained in other cases.;-)
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 GENERAL APPROACHES TO THE STUDY OF FEEDING 1. Control of Body Weight Is there homeostatic regulation of our body weight ? Do we defend a body weight " set point" ? It seems like there should be. Animals (except humans and other critters in captivity) don’t get fat. They seem to regulate pretty well. In fact, it seems that most animals (including humans) don’t regulate calories or nutrients within a meal but do so over a several week period. Energy expenditure and food intake are NOT strongly correlated within a 24-hour period , but there IS a strong correlation if weekly intake and energy expenditure are examined. The figure on the right contains data showing that energy expenditure and caloric intake are not correlated within a single day (top panel), but are linearly correlated over a week-long period (bottom panel). This meansthat control of a meal is not particularly homeostatic . 2. Control of a Meal
Image of page 2
• What makes us start eating? (hunger) • What makes us stop ? (satiety) • Why can’t we eat just one M and M? (reward) Consider the following diagram for a bit... This diagram shows the behavioral sequence of eating and the potential feedback controls via the brain. The two arrows at the top of the diagram pointing to the brain indicate that external influences (smells, time of day, social stimulation, stress) can trigger food search without information from an empty stomach or from nutrient absorption. So we can “need” to eat because we are getting signals that we need food, or we can “desire” to eat because of signals that stimulate desire. Similarly, we may stop eating because a signal tells us that our tummy is full , or because a signal tells us that we have ingested enough nutrients to meet our immediate needs.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern