MYP Biology: Nutrition & a Balanced Diet FAQ

It's tricky because it looks like GCSE-level common knowledge, so students under-revise it, then lose marks on Criterion D questions asking them to explain a mechanism — like why vitamin C deficiency causes scurvy — rather than just naming the food group. Recall isn't enough; you need cause-and-effect reasoning.

A balanced diet supplies the right proportions of carbohydrates, proteins, fats, vitamins, minerals, fibre and water to meet an individual's energy and growth needs — and that proportion changes with age, activity level, and health status. MYP assessments usually ask you to evaluate a sample diet against a specific person's needs, not a generic ideal.

A nutrient is a single chemical the body needs (like glucose or calcium); a food group clusters foods sharing a main nutrient (dairy, grains); a diet is the overall pattern of what someone eats over time. Exam answers that muddle these three lose clarity marks fast — always name the specific nutrient first.

Carbohydrates, proteins, lipids (fats), vitamins, minerals, fibre and water — each with a distinct function, a named deficiency condition, and common food sources. Students who lose marks usually can name the nutrient but not pair it with its specific deficiency disease and symptom.

BMI = mass in kilograms ÷ (height in metres)², and IB-style questions usually give you the raw numbers and ask you to calculate, classify, then discuss limitations — BMI doesn't distinguish muscle from fat, so it's a screening tool, not a diagnosis.

Expect 'state', 'describe', 'explain' and 'evaluate' — each demanding a different depth of answer. 'State' wants one fact (e.g. name a nutrient); 'explain' wants a mechanism with reasoning ('because...'); 'evaluate' wants you to weigh strengths and limitations, often of a diet plan or a data set.

Nutrition connects directly to digestion (enzyme action on food groups), respiration (how glucose from carbohydrates releases energy), and homeostasis (blood glucose regulation). Assessment tasks often blend nutrition with one of these, so isolated revision of nutrient facts alone won't cover exam-style synthesis questions.

Nutrition tasks usually sit under Criterion A (Knowing and understanding) for recall of nutrients and functions, and Criterion D (Reflecting on the impacts of science) when you're asked to evaluate diets, food security issues, or health campaigns. Some units also use Criterion C (Processing and evaluating) if you're analysing dietary survey data.

Re-reading doesn't build the exam skill you need — active recall and application do. Build a nutrient-deficiency table from memory, then practise past-paper style questions that ask you to explain (not just state) why a deficiency causes its symptoms.

The most common mistake is naming the nutrient group correctly but skipping the mechanism — writing 'lack of vitamin C causes scurvy' without saying why (vitamin C is needed for collagen synthesis, so its absence weakens connective tissue). That missing 'because' is usually where the mark is lost.

Nutrition feels basic because your child already knows the everyday facts — fruit has vitamin C, milk has calcium — but MYP Biology assessment wants biological reasoning, not general knowledge. The jump from 'what' to 'why and how' is where marks are actually lost, and it's a skill that needs deliberate practice, not just familiarity with the content.

The most useful thing you can do is quiz them on 'why', not 'what' — ask 'why does a lack of vitamin D cause rickets?' rather than 'what does a lack of vitamin D cause?'. That small shift mirrors exactly how MYP questions are phrased, and it's free, no resources needed.