Comprehensive Nutrition and Food Science Review for Students

Diet

The food and drink you eat regularly eat and drink.

Nutrition

The science that studies food and its relationship to health.

Fibre

A type of carbohydrate that humans cannot fully digest.

Glycemic Index

A ranking of carbohydrates based on how fast they are broken down by the body into monosaccharides and raise blood sugar levels.

Insulin

A hormone that lowers your blood sugar.

Glucagon

A hormone that raises your blood sugar.

Protein

large molecules made of chains of amino acids.

Energy

Most food is converted to heat or energy.

Essential Nutrients

Nutrients that cannot be made by the human body and must come from the food we eat.

Non-essential Nutrients

Needed by the body to be healthy. Can be made by the body from other nutrients if missing in the diet.

Macronutrients

Needed in the body in large quantities daily.

Micronutrients

Needed in the body in tiny quantities daily.

Main Function of Carbs

They are the main source of energy for our bodies, particularly the brain.

Glycogen

A long chain of glucose molecules bonded to each other. Stores glucose in the liver and muscles for later use.

Monosaccharides

Single sugars (glucose, galactose, fructose).

Disaccharides

Double sugars (sucrose, lactose, maltose).

Polysaccharides

Starch, glycogen, cellulose.

Benefits of Fibre

Improves digestion, prevents constipation, lowers cholesterol, controls blood sugar, and helps maintain healthy weight.

High GI Foods

Food with a GI higher than 70 are rapidly digested, absorbed and cause strong fluctuations in blood sugar levels.

Low GI Foods

Food with a GI lower than 55 are slowly digested, absorbed, and produce gradual changes in blood sugar levels.

Insulin's Role

Increases glucose uptake and simulates glycogen synthesis.

Glucagon's Role

Raises blood sugar by breaking down glycogen into glucose.

Relationship between Glycemic Index and Insulin

High GI food cause blood sugar spikes, which trigger large insulin releases. Low GI foods leads to steadier blood sugar, reducing stress on the body and lowering the risk of diabetes.

Triglycerides

The fats and oils in the body. Made of one glycerol molecule and three fatty acids.

Functions of Fats

Long term energy store, provide building blocks for steroid hormones and cholesterol, provides essential fatty acids (omega 3 and omega 6), vitamin absorption, building cell membrane, insulation and cushioning.

Monounsaturated Fats

Has one double bond, usually liquids at room temperature, lowers risk of heart disease and stroke and mostly from plant sources.

Polyunsaturated Fats

Has many double bonds between carbons, usually liquids at room temperature, from fatty fish and plant sources, and good for brain development and lowering risk of heart disease.

Saturated Fats

Has no double bonds between carbons, solid at room temperature, from animal sources, increases risk of heart disease.

Trans Fats

Artificially altered double bonds, unsaturated fats turned to a solid form of hydrogenation, raises LDL cholesterol, and lowers HDL, creates inflammation and can lead to heart disease, stroke and type 2 diabetes.

Proteins Functions

Build and repair tissues, form enzymes and hormones, and support muscle and immune system health.

Essential Amino Acids

There are 9 essential amino acids that the body cannot make. They must come from food like meat, eggs, and beans.

Importance of daily protein

Protein is needed for muscle repair, cell growth, and enzymes. Without enough, the body breaks down muscle for energy, causing weakness, poor healing, and lower immunity.

Sources of protein

Protein sources include meat, dairy, eggs, beans, nuts, and tofu.

Complete proteins

) have all essential amino acids.

Incomplete proteins

missing some amino acids, but can be combined.

Vitamins

organic compounds needed in small amounts for body functions.

Vitamins as coenzymes

Many act as coenzymes to help enzymes do their jobs.

Vitamins as antioxidants

Some, like vitamins C and E, act as antioxidants that protect cells from damage caused by free radicals.

Fat-soluble vitamins

vitamins (A, D, E, K) are stored in body fat and can build up to toxic levels.

Water-soluble vitamins

vitamins (B, C) dissolve in water, are not stored, and must be replenished daily.

Minerals

are inorganic nutrients that support body functions.

Examples of minerals

Examples: calcium (bones/teeth), iron (carries oxygen in blood), potassium (nerve function).

Sodium consumption in Canadians

Too much sodium increases risk of high blood pressure, heart disease, and stroke.

Sources of sodium in diet

Most sodium comes from packaged, processed, and restaurant foods, not from salt added at home.

Importance of water

Water regulates temperature, carries nutrients, removes waste, and cushions joints.

Daily water loss and intake

We lose about 2-3 liters daily through sweat, urine, and breathing, and need to replace it with fluids and water-rich foods.

Calorie

the unit of energy in food. Scientifically, it's the amount of heat needed to raise 1 kg of water by 1°C.

Calories in macronutrients

Carbohydrates = 4 Calories per gram. Proteins = 4 Calories per gram. Fats = 9 Calories per gram.

TEE

Total Energy Expenditure is the total Calories a person burns daily.

Factors affecting calorie burn

No, energy needs depend on factors like age, body size, gender, activity level, and metabolism speed.

Consequences of calorie imbalance

Too many Calories cause weight gain, obesity, and related diseases. Too few Calories cause weight loss, fatigue, nutrient deficiencies, and weak immunity.

Food guides

government tools that provide advice on healthy eating patterns.

Purpose of food guides

They were introduced to help prevent malnutrition and chronic disease.

Recent changes to Canada's food guide

Focus on more plant-based proteins, fruits, vegetables, and whole grains. Water is recommended over sugary drinks. Less emphasis on meat and dairy.

Nutrition labels

Labels show serving size, Calories, nutrients, and % Daily Value.

Foods requiring labels

Packaged foods like cereal or canned soup require labels. Fresh fruits, vegetables, bakery items, and raw meats usually don't.

% Daily Value (%DV)

shows how much a nutrient in one serving contributes to daily needs.

Recent changes to food labels

Larger, easier-to-read fonts, updated serving sizes, added sugar information, and clearer %DV guidelines.

Ingredient listing on labels

Listed in descending order by weight, so the first ingredients make up most of the product.

Comparing nutrition labels

Choose the one with less sugar, sodium, and saturated fat, and more fibre, protein, vitamins, and minerals.

Diet description improvements

Suggestions may include adding more vegetables, whole grains, lean proteins, and water, while reducing processed foods, added sugars, salt, and unhealthy fats.

Food choices and environment

We can reduce meat and processed foods, eat local and seasonal produce, waste less food, recycle packaging, and choose sustainable options to protect the environment.