BIOL217 - Week 5

Blood sugar spike:
- Cold-pressed juices can contain more concentrated sugars due to the removal of fiber, which typically slows sugar absorption.
- Generally not problematic for healthy individuals without blood sugar issues but may cause minor issues such as increased hunger and energy swings.
- Suggestions for mitigation include:
  - Adding fiber (e.g., chia or flax seeds, almonds, or walnuts).
  - Pairing juices with protein sources such as protein powder, eggs, or Greek yogurt.
  - Choosing lower glycemic index fruits and vegetables, such as berries and green leafy vegetables.

Evidence does not fully support claims that NNS leads to weight gain, increased cravings, or hunger.
Replacing sugar with NNS may aid in weight control, as many studies demonstrate that consumption of NNS-sweetened foods does not elevate sweetness preference or energy intake.
The replacement of sugar does not seem to contribute significantly to compensatory energy intake, implying it doesn't hinder weight loss.

Sam is a 20-year-old university student whose grandfather died of a heart attack at age 50.
A recent heart disease risk assessment indicated he is 10 kg (25 lb) overweight with elevated body fat percentage and a cholesterol level of 5.4 mmol/L (normal < 5.2 mmol/L).

Despite being 20, Sam's lifestyle includes:
- High intake of red meat and limited servings of fruits and vegetables (1-2/day).
- Drinking whole milk and snacking on ice cream nightly.
- Minimal physical activity (Frisbee only once a week and weightlifting once a week).

Various family members offer different dietary adjustments:
- Girlfriend: Eliminate meat (vegetarian perspective).
- Biology lab partner: Cut out all fats.
- Sister: Adopt the Mediterranean diet (pasta with olive oil).
- Roommate: Increase fish intake.
- Mother: Incorporate more nuts (e.g., almonds, walnuts).
It is crucial to evaluate the validity of these recommendations and formulate a balanced approach for Sam.

Lipids are organic molecules collectively referred to as fats, characterized by their insolubility in water (e.g., oil and vinegar).
Types include fatty acids, triglycerides, phospholipids, and sterols.
Fats and oils provide 9 calories per gram.

The most common form of dietary fat, constituting about 95% of fat intake.
Essential for energy storage, consisting of three fatty acids attached to a glycerol backbone, functioning as energy packages.

Initial breakdown of fats occurs in the stomach, with a more extensive digestion in the small intestine.
Bile from the liver and enzymes from the pancreas break down triglycerides into fatty acids and glycerol for absorption through the small intestine walls into the bloodstream.
Re-synthesized triglycerides in the liver are packaged into lipoproteins for transportation due to their water insolubility.
Triglycerides stored in fat cells can be broken down into fatty acids and glycerol for energy production.

When intake exceeds energy needs, excess calories are converted into triglycerides and stored within adipose tissues, leading to fat cell growth.
Energy use triggers fat cell shrinkage during calorie deficit or increased physical activity.

Fat cells can shrink but do not disappear upon weight loss, maintaining a balance between energy storage and expenditure is vital for health.

Key types include:
- Saturated fatty acids: No double bonds, solid at room temperature, found in animal products (meat, butter).
- Unsaturated fatty acids: Contain one or more double bonds, liquid at room temperature, found in plant oils and fatty fish.

Commonly found in:
- Animal products: Meat, butter, cheese.
- Certain plant-based sources: Coconut oil, palm oil, cocoa butter.
Attributes include taste, texture, stability at high temperatures, and long shelf life (resistance to rancidity).

Types:
- Monounsaturated Fats (MUFA): One double bond; found in olive oil, avocados, nuts.
- Polyunsaturated Fats (PUFA): Multiple double bonds; can include omega-3 and omega-6 fatty acids.
Essential fatty acids (omega-3 and omega-6) must be derived from the diet.

Formed via hydrogenation, turning liquid oils into solid fats.
Associated with raised LDL cholesterol and reduced HDL cholesterol, increasing heart disease risk and inflammation.
Canada has prohibited trans fats in food since 2017 due to these health risks.

Types include cholesterol (animal-derived) and plant sterols (reducing cholesterol absorption); essential for health and hormone regulation.

Various factors, including dietary fat types, influence cancer risk.
High saturated fat is linked to increased risks for colon cancer; unsaturated fats may offer protection.

High LDL cholesterol from saturated fats increases incidence of heart disease due to plaque buildup in arteries (atherosclerosis).
Changing dietary patterns can lower the risk of heart disease, emphasizing the intake of beneficial fats from plant sources, fish, and nuts.

Total fat intake should be 20%-35% of total calories. Limit saturated and trans fats for optimal health.

Choose healthier fats (e.g., omega-3 sources), read food labels for fats, and maintain balanced dietary intake along with physical activity.