Topic 6- Weight management

Question 1

• What is body weight a result of?

Answer 1

It is a result of the balance between energy intake vs. output

Question 2

• What happen is energy intake in greater than output?

Answer 2

Fat deposition occurs

Question 3

• What happens in energy output in greater than input?

Answer 3

Fat depletion occurs

Question 4

• What are adipocytes?

Answer 4

They are fat cells designed to store fat in the body and an energy reserve. This is an efficient function due to low water storage and the high density on fat. They are also known as lipocytes.

Question 5

• What does the amount of fat stored depend on?

Answer 5

Depends on the number os fat cell and how big they are.

Note! They can expand up to 20 times their size. They restart cell division when full.

Question 6

• During what period do fat cell numbers mainly increase?

Answer 6

Durning childhood and puberty

Question 7

• Obesity is due to two things, What are they?

Answer 7

• Obesity due to and increase in cell number in hyper plastic
• Obesity due to increase in size in hypertrophic
  Note! both usually occur together

Question 8

• What are adipocytes (lipocytes or fat cell) composed of?

Answer 8

Adipose tissue, specialised in storing energy as fat. There are two types - White and brown

Question 9

• What the difference between white adipose tissue (WAT) and brown adipose tissue (BAT)?

Answer 9

White is the fat storage tissue and brown tissue produces heat

Question 10

• What happen with the heat created by the brown adipose tissue?

Answer 10

The heat release in performed by the mitochondrial uncoupling protein 1 (UCP1) which is activated by the diet, in the mitochondria.

Question 11

• What is BAT commonly called baby fat?

Answer 11

This is because it is present in babies but convert to WAT in adult hood due to UCP1 ceasing to work

Question 12

• What do white fat cells (also called monovacuolar) contain?

Answer 12

They contain a large liquid droplet surrounded by a later of cytoplasm. The nucleus is flattened and located on the periphery

Question 13

• What is the size of a typical fat cell?

Answer 13

0.1mm in odometer with some being twice that size and other half that size

Question 14

• What state is fat stored in and compose of?

Answer 14

It is stored in a semi-liquid state and composed primarily of triglycerides and cholesteryl ester

Question 15

• What do white fat cells secrete?

Answer 15

Many protein acting as adipokines such as resistin, adiponectin and leptin

Question 16

• How many fat cells does the average adult have?

Answer 16

30 billion fat cells. If excess weight is gained as an adult, fat cell increase in size about fourfold before dividing and increase the absolute number of fat cells present

Question 17

• What is the shape brown fat cells?

Answer 17

Brown fat cells or plurivacuolar cells are polygonal in shape and have a considerable cytoplasm with lipid droplets scattered throughout. The nucleus is round and is not in the periphery of the cell. The brown colour comes from the large quantity of mitochondria

Question 18

• What is the storage of fat cells controlled by?

Answer 18

Controlled by the enzyme ‘lipoprotein lipase (LPL)’

Question 19

• How does the enzyme lipoprotein lipase work?

Answer 19

It breaks down the triglycerides into fatty acids and glycerol, small enough to enter the cell. In the cell they rejoin to become triglycerides.

Question 20

• What is lipoprotein lipase?

Answer 20

It is water soluble enzyme that hydrolyses triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fat caidsand one monoglyceride molecule.

The LPL is attached to the luminal surface of endothelial cells in capillaries.
It is most widely distributed in adipose, heart, and skeletal muscle tissue.
When there is more LPL on fat cell people store more fat easily

Question 21

• Can the adipocyte secrete signalling messenger, called adipokines, that act as an endocrine cell?

Answer 21

Yes

Question 22

• Do adipocyte in different parts of the body have the same levels of enemies responsible for fat breakdown and removal?

Answer 22

NO - Different parts of the body have different levels of enzymes responsible.

Question 23

• What is one of the most critical metabolic facts responsive for weight regain?

Answer 23

Is the increase in LPL activity following weight loss. Hight loss acts as an integral signal to the genes to produce more LPL to store more fat.

Question 24

• In terms of BMI, what is defined as obese?

Answer 24

BMI of over 30

Question 25

- How does genetics effect obesity?

Answer 25

Genetics determines a person susceptibility to becoming obese. Different people are able to gain to lose more weight on the exact same diet/exercise.

Question 26

- What is leptin and how is it involved in weight regulation?

Answer 26

There is one gene involved in weight regulation which codes for a hormone called leptin. When the body gains dat, leptin production (from adipocytes) increases, resolution in weight loss. Some obese people have low leptin caused by a defective ‘ob’ gene.

Question 27

- What is Ghrelin and what does it do?

Answer 27

It is a protein hormone secreted by stomach cells. It promotes positive energy balance by stimulating appetite and promoting fat storage. Blood levels read before a means and fall afterwards in proportion to energy consumes. Generally lean people have high ghrelin levels and obese people low. Grossly obese prader-willi syndrome patient have chronically high ghrelin levels even after large meals. Ghrelin tends to keep a person weight constant and maximised fat storage during times of famine. People who lack sleep also tend to have high ghrelin levels.

Question 28

- When fat releases energy what can it be in the form of?

Answer 28

Directly as health or captured as ATP. The capture on energy release by cellular oxidation as ATP bound energy requires a set of couples protein in the mitochondria.

Question 29

- What does uncoupled proteins do?

Answer 29

They oppose wight gains and effect BMR

Question 30

- What percentage of all people who lose weight maintain that weight loss?

Answer 30

5%

Question 31

- What are the medical consequences of obesity?

Answer 31

Obese people die younger, suffer more heart attacks, strokes and concert and have greater incidence on type 2 diabetes

Question 32

- What are repeated rounds on weight loss and regain termed as?

Answer 32

Yo-yo dieting

Question 33

- What does rapid wight loss do to metabolism and LPL?

Answer 33

Rapid weight loss lowers the metabolism (BMR) and increases LPL efficiency making fat deposition easier. When people return to normal diet after dieting, rapid fat gain results and weight often passes their previous peak weight.

Question 34

- How do obesity drugs work?

Answer 34

The suppress appetite by raising serotonin levels in the brain. Some found to cause hypertension and valve damage

Question 35

- What are some herbal weight loss products?

Answer 35

- St johns worj - Ma Huang Harbal laxatives: Senns, Aloe, rhubarb, cascara, castor oil and buck thorn

Question 36

- What are very low calorie diets can what can the side effects?

Answer 36

They are generally defined as those containing less that 3500KJ per day The down sides include: - body got into starvation mode - become efficient and storing energy - BMR slows down - prepares for rapid weight gain - can then cause higher weight gain

Question 37

- What are some reasonable treatment of obesity?

Answer 37

- Focus of health gains, not just weight - consider dietary guidelines - small slow losses are more likely to me maintained - modest weight loss can improve blood pressure, cholesterol and symptoms of diabets - can help reduce disease risk - reasonable weight loss is 10% in six months

Question 38

- Causes of underweight?

Answer 38

- Hypothalamic irregularities of the hugher-appitite satiety process, psychological traits, metabolic processes, food aversions and hereditary tendencies