Nutrition Fundamentals: Reading a Food Diary & Building a Food Plan

1. What a food diary is for. It is a conversation tool, not a measurement. It shows patterns (timing, variety, convenience foods, drinks, eating alongside work or screens) that a verbal "I eat well" cannot. Read it for patterns first, numbers second.
2. Its limits: people under-report. A review of studies comparing self-reported intake with energy expenditure measured by doubly labelled water found that reported intake is generally lower than measured expenditure when people record their own intake, by roughly 2–30% in adults, with the gap larger in obese people (up to about 59% in some studies) and in restrained eaters (Hill & Davies, 2001). Practical consequences: treat reported calories as a floor, do not use a diary to "prove" someone is lying, and ask open questions about what is usually missing (snacks, drinks, weekends, portions).
3. A reading method (five passes). (1) Regularity: meals, gaps, late eating. (2) Variety: plants of different colours, protein sources, fats. (3) Quality: how much comes from whole or minimally processed foods versus ultra-processed foods. (4) Fluids and alcohol. (5) Context: who cooks, budget, shift work, culture, faith-based fasting, appetite, symptoms after meals. Finish by naming one strength to keep before suggesting any change.
4. Fibre and food quality. A series of systematic reviews and meta-analyses for the WHO found that higher fibre intake was associated with lower all-cause mortality, coronary heart disease, type 2 diabetes and colorectal cancer; in dose-response analyses of prospective studies, each additional 8 g a day of fibre was associated with, for example, a relative risk of 0.93 for all-cause mortality and 0.85 for type 2 diabetes incidence (Reynolds et al., 2019). Limits: these are observational associations for fibre-rich whole foods, not proof that adding a fibre supplement gives the same effect.
5. Ultra-processed food. In a small inpatient randomised crossover trial (20 adults, two weeks on each diet, meals matched for presented calories, sugar, fat, fibre and macronutrients), people ate about 508 kcal a day more on an ultra-processed diet than on an unprocessed diet and gained about 0.9 kg, while losing about 0.9 kg on the unprocessed diet (Hall et al., 2019). Limits: small, short, in a controlled setting. It shows an effect on intake under those conditions; it does not tell you which feature of the food caused it or what happens over years.
6. Dietary patterns. In PREDIMED, 7,447 Spanish adults at high cardiovascular risk were randomised to a Mediterranean diet with extra-virgin olive oil, a Mediterranean diet with nuts, or a reduced-fat control; over a median 4.8 years the hazard ratios for a major cardiovascular event were 0.69 (olive oil) and 0.72 (nuts) versus control (Estruch et al., 2018). Limits: the original 2013 report was withdrawn and re-analysed because some participants were not randomised as planned; the revised estimates are the ones to cite. Teach this as a pattern that is easy to personalise by culture (many cuisines are plant-forward, legume-rich and oil-based), not as one prescribed diet.
7. Protein, especially for older people. The PROT-AGE position paper recommends at least 1.0–1.2 g of protein per kg body weight a day for older adults, higher (1.2 g/kg or more) for active people and 1.2–1.5 g/kg for those with acute or chronic illness, with severe kidney disease not on dialysis as an exception where protein may need limiting; it says the evidence is not yet strong enough to make specific recommendations on protein type, timing or supplements (Bauer et al., 2013). Link back to sarcopenia (Lesson 4.4).
8. Building a food plan: a five-step method. (1) Start from the person's goal, health picture and what they already eat. (2) Pick no more than two or three changes, in plain food language, ahead of any supplement. (3) Build around what they will realistically buy and cook: budget, time, culture, household. (4) Write it as a one-week outline with swaps, not a rigid menu. (5) Agree how you will know it is working (energy, sleep, bloods, waist, adherence) and a review date. Always screen first: pregnancy, eating-disorder history, diabetes treatment, kidney disease, allergies and medicines that interact with food all change what is safe to advise.
9. Recognising possible deficiency (recognise, record, refer). Diet that is very limited, restricted for long periods, or strictly plant-based without planning, can leave gaps. Learners learn to notice patterns that justify a clinician's assessment (very narrow intake, unexplained fatigue, hair or skin changes, tingling, heavy periods, recent weight loss) and to record them, not to diagnose or to prescribe doses. [⚠ Clinical reviewer to supply the nutrient-by-nutrient recognition table (e.g. iron, B12, vitamin D, folate) with sources before go-live; no thresholds or doses are stated in this draft.]
10. Scope. Practitioners (doctors, nurses, pharmacists, allied clinicians) take a nutritional history, request investigations and treat deficiency within their registration. Coaches design general healthy-eating plans for people without medical conditions that require dietetic care, and refer anyone with a diagnosed condition, suspected deficiency, eating-disorder signs or complex needs to the right clinician or dietitian.

Learners read one anonymised sample diary and produce (a) a five-pass reading and (b) a one-week food plan outline with review date and referral flags (~45–60 minutes).

A 58-year-old woman's diary shows toast and tea until a large evening meal, almost no protein before 6 pm, and she says she has "no appetite." She is losing weight without trying. What do you do?

(Answer to teach: unintentional weight loss is a signal for clinical assessment, not a coaching goal. Record it, do not build a plan around it, and refer.)

What would your own three-day food diary say that your sentence "I eat fine" would not?

• López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. The hallmarks of aging. Cell 2013;153:1194–1217; and The hallmarks of aging: an expanding universe. Cell 2023;186:243–278. (As cited in Module 1.)
• Epel ES, Blackburn EH, Lin J, Dhabhar FS, Adler NE, Morrow JD, Cawthon RM. Accelerated telomere shortening in response to life stress. Proc Natl Acad Sci USA 2004;101(49):17312–17315.
• Telomere Research Network. Recommendations for the measurement of telomere length in population studies (precision and measurement error).
• Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. J Clin Sleep Med 2015;11:591–592.
• Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 2010;33:585–592.
• McEwen BS. Protective and damaging effects of stress mediators. N Engl J Med 1998;338:171–179.
• Levy BR, Slade MD, Kunkel SR, Kasl SV. Longevity increased by positive self-perceptions of aging. J Pers Soc Psychol 2002;83:261–270.
• Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing 2019;48:16–31.
• WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet 2004;363:157–163.
• Joshi P, Islam S, Pais P, et al. Risk factors for early myocardial infarction in South Asians compared with individuals in other countries. JAMA 2007;297:286–294.
• Type 2 diabetes in migrant south Asians: mechanisms, mitigation, and management. Lancet Diabetes Endocrinol 2015;3:1004–1016.
• Alshamsi MA, Fatima W, Al Teneiji MT, Srinivasamurthy SK. Vitamin D status among apparently healthy individuals in the UAE: a systematic review. Front Nutr 2025;12:1604819.
• Oppenheim A, Jury CL, Rund D, Vulliamy TJ, Luzzatto L. G6PD Mediterranean accounts for the high prevalence of G6PD deficiency in Kurdish Jews. Hum Genet 1993;91:293–294.
• Kling J. Race-, ethnicity-based clinical guidelines miss the mark: study (report of Siddique S, Digestive Disease Week 2022). MDedge Family Medicine, 27 May 2022.
• Kauff ND, Perez-Segura P, Robson ME, et al. Incidence of non-founder BRCA1 and BRCA2 mutations in high risk Ashkenazi breast and ovarian cancer families. J Med Genet 2002;39:611.
• El-Shanti H, Majeed HA, El-Khateeb M. Familial Mediterranean fever in Arabs. Lancet 2006;367:1016–1024.
• De Sanctis V, Kattamis C, Canatan D, Soliman AT, et al. β-Thalassemia distribution in the Old World: an ancient disease seen from a historical standpoint. Mediterr J Hematol Infect Dis 2017;9(1):e2017018.
• Ojo AO, et al. APOL1 kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Kidney Int 2025;108:763–779.
• Emmett E, O'Connell M, et al. South London Stroke Register analysis of ethnic and socioeconomic inequalities in stroke (30-year data). eClinicalMedicine 2026 (as reported by King's College London, July 2026).
• Brooks PJ, et al. The alcohol flushing response: an unrecognized risk factor for esophageal cancer from acetaldehyde exposure. PLoS Med (as reported in press coverage).
• American Diabetes Association guidance lowering the diabetes screening BMI threshold for Asian Americans to 23 (2015), as summarised by diaTribe. Press coverage differs on the exact wording and later changes; confirm the current ADA position before relying on it.
• Leong DP, Teo KK, Rangarajan S, et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. Lancet 2015;386:266–273.
• Northey JM, Cherbuin N, Pumpa KL, Smee DJ, Rattray B. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. Br J Sports Med 2018;52(3):154–160.
• Hill RJ, Davies PSW. The validity of self-reported energy intake as determined using the doubly labelled water technique. Br J Nutr 2001;85:415–430.
• Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet 2019;393:434–445.
• Hall KD, Ayuketah A, Brychta R, et al. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab 2019;30:67–77.
• Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med 2018;378(25) (page range to confirm).
• Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc 2013;14(8):542–559.
• World Health Organization. Guidelines on physical activity and sedentary behaviour. 2020.