Exercises: A healthy diet

Name the groups of nutrients that a complete diet must include (proteins, carbohydrates, lipids, vitamins, mineral salts and water) and state a general function of each group in the body.

The food wheel shows several food groups labelled with letters, with larger sectors indicating a greater presence required in the daily diet. State which letter occupies the sector that should dominate our diet, which food group it corresponds to, and which letter indicates the group whose consumption should be occasional.

Explain why breakfast is considered an important meal, especially for school-age children, and describe a balanced breakfast indicating which nutrients are provided by each food item you include.

Analyse this one-day menu: breakfast, a pre-packaged pastry and a soft drink; lunch, a burger with chips and a soft drink; dinner, pizza. Point out what problems it presents from the perspective of a balanced diet and suggest three specific changes to improve it.

The Mediterranean diet is considered a healthy model. Describe its main characteristics (predominant foods, primary fat source, consumption frequency for each group) and compare it with the typical diet of many teenagers today.

A 14-year-old female athlete needs about $2200\ \text{kcal}$ per day. If her breakfast provides about $450\ \text{kcal}$, calculate what percentage of her daily energy intake is covered by breakfast and reason whether it complies with the recommendation that breakfast should provide around $25\ \%$ of daily calories.

A supplement company promotes snack bars claiming they contain "$100\ \%$ of the non-essential nutrients your body needs", and asserts that thanks to this "it is no longer necessary to worry about eating fruit, vegetables, or legumes".\na) Scientifically refute this advertisement by explaining the difference between an essential and a non-essential nutrient, and give two examples of each group.\nb) Predict what biological consequences a person who based their diet solely on these bars would suffer, and justify why no single food—no matter how complete it is advertised to be—can replace a varied diet.

Imagine that you observe the following changes in a $14$-year-old classmate: they systematically skip recess snack saying they already ate at home, show constant worry about the calories in any food, have noticeably lost weight, and when the group suggests eating pizza, react with distress and isolate themselves.\na) Interpret these signs and deduce what type of eating disorder (ED) could be developing, comparing its main characteristics with those of bulimia.\nb) A friend suggests: "Let's not say anything to anyone; it's just a lack of willpower, it will pass". Refute their stance using biological and psychological arguments, and design a responsible action plan to seek immediate professional help from the school environment.

The nutrition label on a package of cookies indicates that every $100\ \text{g}$ contains $20\ \text{g}$ of fat, $65\ \text{g}$ of carbohydrates (of which $30\ \text{g}$ are sugars) and $6\ \text{g}$ of protein. The WHO recommends that free sugars should not exceed $10\ \%$ of daily energy. Knowing that $1\ \text{g}$ of sugar provides about $4\ \text{kcal}$ and that a teenager consumes about $2200\ \text{kcal}$ per day, calculate how many grams of these cookies would reach that limit if they were the only source of sugar for the day, and comment on the result.