All proteins are made of amino acids, but not all proteins contain the same amino acids or in the same proportions. The concept of protein quality addresses this variation — recognising that some protein sources provide all the amino acids the body cannot synthesise (complete proteins) while others lack or are low in one or more essential amino acids (incomplete proteins). For omnivores eating varied diets, protein quality is rarely a concern. For plant-based eaters, understanding it provides the foundation for meeting protein needs effectively.
Essential vs Non-Essential Amino Acids
Of the 20 amino acids used by the human body, nine are essential — the body cannot synthesise them and must obtain them from food. The nine essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Complete proteins contain all nine in adequate proportions; incomplete proteins are deficient in one or more.
Complete Protein Sources
Animal-derived proteins — meat, poultry, fish, eggs, and dairy — are complete proteins, containing all nine essential amino acids in proportions that closely match human requirements. Among plant sources, the complete proteins are: soya (including tofu, tempeh, edamame) — the most complete of plant proteins; quinoa — a grain with all nine essential amino acids; buckwheat; hemp seeds; and chia seeds. These plant complete proteins are valuable for plant-based eaters.
Incomplete Proteins and Complementation
Most plant proteins are limited in one or more essential amino acids. Legumes (beans, lentils, chickpeas) are typically low in methionine but high in lysine. Grains (rice, wheat, oats) are high in methionine but low in lysine. These two groups therefore complement each other — eating both across the day (not necessarily at the same meal) provides the full essential amino acid profile. Traditional food cultures around the world independently developed this principle: rice and lentils (South Asia), beans and tortilla (Latin America), houmous and pitta (Middle East).
Protein Digestibility: PDCAAS and DIAAS
The PDCAAS (Protein Digestibility-Corrected Amino Acid Score) and newer DIAAS (Digestible Indispensable Amino Acid Score) quantify protein quality accounting for both amino acid content and digestibility. Animal proteins score close to 1.0 (maximum); soya protein 0.91–0.99; most other plant proteins 0.5–0.8. The lower digestibility of plant proteins means plant-based eaters need somewhat higher total protein intake to achieve equivalent amino acid absorption.
Eat Well at Vanda's Kitchen
Understanding nutrition is the first step — applying it daily is where Vanda's Kitchen comes in. Our freshly prepared Filipino-inspired food is built around the nutritional principles covered in this article: lean proteins for muscle and satiety, complex carbohydrates for sustained energy, and fresh vegetables for the micronutrients and antioxidants that support every body system. Every item is prepared daily in our EC4 kitchen near St Paul's Cathedral, certified halal, 100% nut-free, and fully allergen-labelled.
For City of London professionals who want consistently nutritious daily lunches without the planning burden, our office delivery service provides fresh, balanced food to your desk. View our team lunch options, WhatsApp us, or send an enquiry. Read our healthy office lunch delivery guide for more.
Put Nutrition Into Practice at Vanda's Kitchen
Knowing the nutritional principles above is one thing — eating well every working day is another. Vanda's Kitchen near St Paul's Cathedral EC4 makes the practical application straightforward. Our freshly prepared Filipino-inspired menu is built around lean proteins, complex carbohydrates, and fresh vegetables — the nutritional combination that supports sustained energy, cognitive performance, and the specific health outcomes covered in this article.
Every item we produce is certified halal (independently verified by the Halal Friendly List), prepared in a 100% nut-free kitchen, and fully allergen-labelled in compliance with Natasha's Law. Our food is stocked in Selfridges Food Hall — confirmation of the quality standard we maintain. For City of London professionals wanting consistently nutritious daily lunches delivered to the office, our team lunch service removes the daily decision without compromising nutritional quality.
To order for your team or enquire about daily delivery: view our team lunch options, WhatsApp us, or send an enquiry. For more on our healthy lunch offer, read our healthy office lunch delivery guide.
Why London Professionals Choose Vanda Kitchen
Vanda Kitchen near St Paul Cathedral EC4 provides City professionals with genuinely nutritious daily lunches that apply the principles covered in this article. Freshly prepared Filipino-inspired food, built around lean proteins, complex carbohydrates, and fresh vegetables. Certified halal (Halal Friendly List). 100 percent nut-free kitchen. 5-star hygiene rating. Full Natasha Law allergen labelling. Selfridges Food Hall quality. For a working lunch that actually supports your afternoon performance, WhatsApp us, send an enquiry, or view our team lunch options.