Dietary Fats

Question 1

Fat content of average American diet: % fat, grams of fat, calories of fat

Answer 1

• % fat = 25-35%
• Grams of fat = 70g for a 70kg person
  
  • 9kcal/gram of fat
• Calories of fat = 630 kcal
  
  • ~30% of 2100kcal daily intake

Question 2

Pool size of stored triglyceride in adipose tissue

Answer 2

• Adipose tissue accounts for ~20-30% of body weight
• 70kg person with 25% body fat = 18kg of triglyceride stored in adipose tissue
  
  • 18kg x 9kcal/g = 157,000kcal of stored energy

Question 3

Pool size of stored triglyceride in liver, skeletal muscle

Answer 3

Contain small amounts of stored triglyceride (hundreds of grams)

Question 4

Physical property differentiating saturated/trans fats from unsaturated fats

Answer 4

• Saturated/trans fats: form crystals at room temperature –> solid
  
  • Lard, manteca, red meat fat
• Unsaturated fatty acids: typically liquid at room temperature
  
  • Olive oil, corn oil, nut oils

Question 5

Examples of foods high in saturated fats

Answer 5

Lard, manteca, fat in red meat

Question 6

Examples of foods high in monounsaturated fat

Answer 6

Oleic acid (found in olive oil, canola oils)

Question 7

Examples of foods high in omega-3 fats

Answer 7

Fish, other seafood

Question 8

Examples of foods high in omega-6 fats

Answer 8

Vegetable oil, corn oil

Question 9

Examples of foods high in polyunsaturated fat

Answer 9

Another way to say omega fat

Walnuts, sunflower seeds, peanut butter, tuna

Question 10

Examples of foods high in trans fat

Answer 10

Margarine, partially hydrogenated oils, palm oil

Question 11

Relationships between high fat diet & adverse health outcomes (atherosclerosis, obesity)

Answer 11

• One possibility: high fat diet promotes weight gain
  
  • Increased energy intake (palatability of high fat diet)
  • Increased energy density
  • Difficulty sensing dietary fat due to small daily flux compared to large stored pool size
• Monounsaturated fats and polyunsaturated fats have beneficial effects on heart disease risk
• Saturated fats and trans fats have adverse effects on CVD risk
  
  • Trans fats demonstrated to be “clearly the worst”

Question 12

Fat components of healthy diet

Answer 12

• Mediterranean diet: fat from olive oil, limited amounts of cheese and yogurt
  
  • Protective for CVD risk
• Unique benefits to omega-3 fats (Eskimos with high fat diet)
• Fish oils prevent arrhythmias, thrombosis, sudden death in people with CAD
• Nut oils are very high in fat but have very long chain lengths and large number of unsaturations
  
  • People who regularly consume nuts –> lower levels oc CVD, reduction in blood lipids
• Plant sterols and stanols
  
  • Modest reduction in serum LDL cholesterol