Nutrition Basics & Food Labeling

Nutrients Basics

• Six Main Elements (CHOPS): Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.

• Six Main Nutrients: Water, Minerals, Vitamins, Carbohydrates, Protein, Fat.

• Human Body Composition (Approximate): Water ($60-70$%), Fat ($15-25$%), Protein ($15-20$%), Minerals ($4-5$%), Carbohydrates (<1%).

Nutrient Categories

• Macronutrients: Needed in large amounts, provide energy (calories).

  • Protein: $4$ calories/gram.

  • Carbohydrates: $4$ calories/gram.

  • Fat: $9$ calories/gram (more calorically dense).

  • Alcohol: $7$ calories/gram (technical, not recommended source).

• Micronutrients: Needed in small amounts (vitamins, minerals).

• Non-Nutrients: Biological effect, no calories, not vitamins/minerals.

  • Examples: Phytochemicals (lycopene, beta-carotene, EGCG), Probiotics, Dietary Fiber (also provides some calories).

Essentiality of Nutrients

• Essential: Body cannot produce, must be obtained from diet (e.g., essential amino acids, iron).

• Nonessential: Body produces (e.g., nonessential amino acids, cholesterol, Vitamin K, Vitamin D from sun).

• Conditionally Essential: Body production is insufficient in specific situations (e.g., glutamine during severe stress, Vitamin D due to lack of sun).

Calories (Kilocalories)

• Definition: Amount of heat required to raise the temperature of $1$ kg of water by $1^ ext{o}C$ ($1$ kilocalorie = $1000$ calories).

• Determining Calories:

  • Bomb Calorimetry: Burning food in a sealed container and measuring heat released.

  • Atwater System: Using general calorie values per gram of macronutrients (Fat: $9$ kcal/g; Protein/Carbs: $4$ kcal/g).

• Calorie Balance:

  • Maintenance: Intake = Total Daily Energy Expenditure (TDEE).

  • Deficit: Intake < TDEE (leads to weight loss).

  • Surplus: Intake > TDEE (leads to weight gain).

  • TDEE includes basal metabolic functions (non-activity thermogenesis) and physical activity.

Food Intake Drivers and Satiety

• Appetite (Psychological): Driven by cravings, environment, sensory inputs (smell, sight, sound).

• Hunger (Physical): Physical need for calories, indicated by symptoms like stomach pain, dizziness, irritability, low blood sugar.

• Satiety: Physical and psychological satisfaction after eating.

  • High Satiety Foods: Protein and Fiber (slow to digest, prolong fullness).

  • Low Satiety Foods: Simple carbohydrates (digest quickly, lead to quicker hunger).

  • Influenced by protein, fiber, water content, and glycemic index.

  • Not directly related to calorie content.

Nutrient Density vs. Calorie Density

• Nutrient Density: High amount and variety of nutrients (vitamins, minerals, phytochemicals) per serving.

• Calorie Density: High in calories per serving.

  • Focus on both is important to avoid malnutrition (over-consumption of calories with insufficient nutrition).

• Variety in Diet: Essential for diverse nutrient intake, gut health, disease prevention, and sustainable enjoyment of food.

Canadian Food Labels

• Purpose: Make informed food decisions, crucial for therapeutic diets.

• Required Components: Nutrition Facts Table, Ingredient List, Claims, Food Allergen Labeling, Date Label.

• Nutrition Facts Table:

  • Serving Size: Amount typically consumed in one sitting (in household measures and metric units).

  • Calories: Estimated per serving, must be within $20$% accuracy.

  • Nutrients Listed: Total Fat (including saturated), Total Carbs (including fiber and total sugar), Protein.

  • Mandatory Micronutrients: Potassium, Calendars, Iron.

  • Other Concerns: Cholesterol, Sodium.

  • % Daily Value (%DV): Indicates the proportion of a nutrient in a serving relative to a $2000$-calorie diet.

    • <5% is 'a little'; >15% is 'a lot'.

• US vs. Canadian Label Differences:

  • US labels specify added sugars; Canada labels total sugar.

  • US $$: >20% means 'a lot' (Canada: >15%).

  • US labels require Vitamin D; Canada does not.

• Front of Package Labels (Canadian): Identifies foods high in sodium, saturated fat, or sugar.

• Nutrition Claims (e.g., "Free," "Low," "Reduced," "Source of," "High in," "Lean," "Extra Lean"): Terms have specific regulatory definitions regarding nutrient content.

• Food Allergen Labeling: Must declare priority allergens (e.g., milk, eggs, peanuts, wheat). "May contain" is optional for cross-contamination risk.

• Date Labeling:

  • Best Before: Indicates optimal quality, not safety.

  • Expiry Date: Food is unsafe to consume past this date.

  • Non-perishable foods (shelf life >$90$ days) are exempt from "best before" dates.