Eating for Your Situation

TL;DR. The general advice in this book applies to most people most of the time. This chapter is the exceptions: the life stages and conditions where a specific nutrient, a specific restriction, or a specific risk changes what you should do. The recurring pattern is that the requirements which matter are few and specific, and the popular advice for each group is usually broader and vaguer than the evidence supports.

1. Pregnancy and trying to conceive

Before conception:

• Folic acid 400 µg daily, from at least a month before conception through 12 weeks. 5 mg if you have had a previously affected pregnancy, diabetes, epilepsy on certain drugs, obesity, coeliac disease, or a family history of neural tube defects. The neural tube closes by day 28, often before pregnancy is known (Chapter 15).
• Review medications with a prescriber. The highest-risk window is over before most people know they are pregnant (Chapter 83).
• Stop alcohol and smoking.

During pregnancy:

Foods to avoid, and why:

Eggs: in the UK, British Lion mark eggs are considered safe raw or lightly cooked, including in pregnancy. Elsewhere, cook them (Chapter 54).

The bigger error remains stopping necessary medication. Contact your prescriber; do not stop unilaterally.

2. Breastfeeding

• Vitamin D 10 µg for the mother; 8.5 to 10 µg daily for the breastfed infant from birth in UK guidance, because breast milk is low in vitamin D.
• Roughly 300 to 500 extra kcal a day.
• Continue iodine and omega-3 attention.
• Alcohol: occasional single drinks are compatible if timed after a feed; there is no need to "pump and dump" beyond convenience, since alcohol leaves milk as it leaves blood.
• Caffeine under 200 to 300 mg; infants clear it very slowly.
• Maternal elimination diets do not prevent allergy and are not recommended (Chapter 98).
• Most medicines are compatible. Unnecessary weaning because of a drug is itself a harm; use a specialist lactation medicines service rather than the package leaflet.

3. Infants and children

• Exclusive breastfeeding or formula for around the first 6 months, with vitamin D supplementation for breastfed infants.
• Introduce solids around 6 months, including allergenic foods from 4 to 6 months and kept in the diet (Chapter 98).
• No honey under 12 months (botulism). No added salt or sugar. No whole nuts, whole grapes, or raw hard vegetables (choking). No rice drinks under 5 (arsenic).
• Iron matters from 6 months, when maternal stores deplete: red meat, pulses, fortified cereal, with vitamin C.
• Full-fat dairy until 2 and whole milk as the main drink from 12 months.
• Fruit juice: none under 12 months, and strictly limited afterwards (Chapter 35).
• Repeated exposure works. Children often need 8 to 15 exposures to accept a new food, and bitterness aversion is developmentally normal, not naughtiness (Chapter 39).
• Do not use food as reward or punishment, and do not force clearing the plate; both are associated with worse self-regulation later.

4. Older adults

The nutritional risks change direction, and undernutrition becomes the bigger problem.

Practical: dentition and swallowing affect what is eaten more than preference does; loneliness and eating alone are associated with poorer intake; and a medication review is often the highest yield nutritional intervention, because polypharmacy causes dry mouth, taste change, nausea, and appetite loss (Chapter 83).

5. Vegetarian and vegan diets

Well-planned plant-based diets are appropriate at all life stages, per the position of major dietetic associations. The gaps are specific and manageable.

Vegan diets in infancy and childhood are possible and require genuine care and ideally dietetic input, because energy density, B12, iron, calcium, and omega-3 all need attention and the margin for error is smaller.

6. Diabetes

• Carbohydrate quantity and quality both matter. Intact grains, pulses, and whole fruit rather than refined starch and juice (Chapter 11).
• Meal order: vegetables and protein before carbohydrate lowers the glucose peak by 30 to 40 percent (Chapter 19).
• A 10 to 15 minute walk after meals lowers the peak substantially.
• Whole fruit is protective, not to be avoided. Juice is not.
• Weight loss can produce remission in type 2 (DiRECT).
• Hypoglycaemia rules if on insulin or sulfonylureas: the 15-15 rule, and beta blockers mask warning signs (Chapter 76).
• Alcohol causes delayed hypoglycaemia, often overnight. Eat carbohydrate when drinking.

7. Chronic kidney disease

The dietary rules invert, and this is where general healthy-eating advice can be actively harmful.

Also: avoid star fruit entirely (Chapter 33), avoid NSAIDs, be careful with potassium-based salt substitutes, and know the sick day rules for holding metformin, ACE inhibitors, ARBs, diuretics, and SGLT2 inhibitors during dehydrating illness.

Potatoes and vegetables can be leached (peel, slice thinly, soak in warm water for hours, boil in fresh water) to reduce potassium substantially.

8. Cardiovascular disease and hypertension

• The DASH and Mediterranean patterns have the best trial evidence.
• Sodium down, potassium up. Consider a potassium salt substitute unless you have kidney disease (Chapter 57).
• Replace saturated with unsaturated fat, not with refined carbohydrate (Chapter 13).
• Oats (3 g beta-glucan/day) and plant sterols (2 g/day) each lower LDL modestly and add to medication.
• Oily fish twice a week.
• Alcohol reduction lowers blood pressure measurably.
• On warfarin: consistent vitamin K, not low (Chapter 38).

9. Gout

The advice has changed substantially and much of what is still repeated is outdated.

• The big contributors are alcohol (especially beer), sugar-sweetened drinks and fructose, red meat, and shellfish.
• Vegetable purines (pulses, asparagus, spinach, mushrooms) are not associated with increased gout risk. The old restriction was based on purine content rather than outcomes and is largely obsolete.
• Dairy is protective, particularly low-fat.
• Coffee and vitamin C are associated with lower risk.
• Cherries have observational and small-trial support for reducing flares (Chapter 25).
• Weight loss helps; crash dieting triggers attacks.
• Diet alone rarely controls gout. Urate-lowering drug therapy is the mainstay, and dietary advice is an adjunct.

10. IBS and gut conditions

• Low-FODMAP as a structured protocol with reintroduction, not a permanent diet, with a dietitian (Chapter 98).
• Soluble fibre (psyllium) helps; insoluble bran often worsens it.
• Enteric-coated peppermint oil has good trial evidence.
• Kiwifruit (two a day) and prunes for constipation-predominant symptoms.
• Garlic-infused oil gives allium flavour without the fructans (Chapter 40).
• Regular meals, adequate fluid, limiting alcohol and caffeine, and addressing stress, which is not dismissive: the gut-brain axis is real and psychological therapies have among the best evidence in IBS.

Inflammatory bowel disease is a different condition requiring specialist care; exclusive enteral nutrition has strong evidence for inducing remission in paediatric Crohn's.

11. Athletes

• Carbohydrate for performance: 30 to 60 g per hour for events over 90 minutes; 60 to 90 g/hour with mixed glucose-fructose sources for very long events.
• Protein 1.6 to 2.2 g/kg, distributed across the day.
• Creatine monohydrate is among the best-evidenced supplements available: 3 to 5 g daily (Chapter 81).
• Caffeine 3 to 6 mg/kg 30 to 60 minutes before (Chapter 88).
• Dietary nitrate (beetroot juice) 2 to 3 hours before, and no antibacterial mouthwash (Chapter 41).
• Hydration: drink to thirst, and beware exercise-associated hyponatraemia in endurance events (Chapter 59).
• Iron status matters particularly in female and endurance athletes.
• Relative energy deficiency in sport (RED-S) is under-recognised: chronic underfuelling causes hormonal disruption, bone loss, and performance decline, in both sexes.
• Buy only certified supplements (Informed Sport, NSF), because contamination means a ban under strict liability.

12. Weight management

• Any diet that produces a sustained energy deficit works; adherence predicts outcome far better than macronutrient ratio.
• Protein and fibre are the two levers with the best satiety evidence.
• Reduce energy density (more volume for the same calories: vegetables, soups, whole fruit).
• Reduce ultra-processed food, on the Hall trial evidence (Chapter 58).
• Resistance exercise plus adequate protein preserves muscle during loss, which matters enormously for what happens afterwards.
• Weight regain is the norm, not a personal failure. Physiological adaptations (reduced metabolic rate, increased ghrelin) actively oppose maintenance and persist for years.
• GLP-1 drugs produce 15 to 20 percent loss and are chronic treatments, not courses (Chapter 76).
• If your relationship with food is distressing, that is the thing to address first. Eating disorders have the highest mortality of any psychiatric condition, and restrictive dieting is a risk factor.

13. The bottom line

• Most people need the general advice. The exceptions are specific and short, and knowing which one applies to you is most of the work.
• Pregnancy: folic acid before conception, vitamin D, iodine, the avoid-list, and above all do not stop necessary medication.
• Infants: introduce allergenic foods early and keep them in; no honey under 12 months, no rice drinks under 5, and no whole nuts or grapes.
• Older adults: more protein, spread across meals, plus resistance exercise, B12, vitamin D, and attention to fluid. Undernutrition is the bigger risk.
• Vegans: B12 is non-negotiable, plus iodine, algal omega-3, iron with vitamin C, and calcium from fortified or low-oxalate sources.
• Kidney disease inverts the usual advice: potassium, phosphate additives, and star fruit all become problems.
• Gout advice has changed: vegetable purines are not the issue; alcohol, sugary drinks, and red meat are.

Sources and notes

Pregnancy and preconception recommendations follow NICE guidance, the UK Start4Life programme, and ACOG. Folic acid dosing follows the MRC Vitamin Study, The Lancet, 1991, and national guidance for higher-risk groups. Food avoidance lists follow FSA and CDC pregnancy guidance. Fish and mercury in pregnancy follows the FSA and Hibbeln et al., The Lancet, 2007. Infant feeding, allergen introduction, honey, and rice drink restrictions follow NHS Start4Life, the BSACI infant feeding guidance, and FSA advice. Repeated exposure and taste acceptance in children follows Wardle and Cooke's work. Older adult protein requirements follow the PROT-AGE and ESPEN expert group recommendations; sarcopenia prevention combining protein with resistance exercise follows those sources. Dehydration in older adults follows Hooper's Cochrane work. Vegetarian and vegan adequacy follows the Academy of Nutrition and Dietetics position paper and the British Dietetic Association vegan factsheet. Diabetes guidance follows Diabetes UK and ADA standards of care, with meal order from Shukla et al. and post-meal walking from Reynolds et al., Diabetologia, 2016. CKD dietary restriction and phosphate additive absorption follow KDIGO and renal dietetic guidance. DASH and Mediterranean evidence follow Sacks et al. and PREDIMED. Gout guidance follows the ACR and BSR guidelines, which de-emphasise vegetable purines; cherries follow Zhang et al., Arthritis and Rheumatism, 2012. IBS management follows NICE CG61 and the BDA low-FODMAP guidance. Sports nutrition follows the ACSM/AND/DC joint position stand and the IOC RED-S consensus statements. Weight management adherence-over-composition follows Gardner et al., JAMA, 2018 (DIETFITS), and Sacks et al., NEJM, 2009; adaptive thermogenesis follows Fothergill et al.'s Biggest Loser follow-up.

Open questions. Almost none of this evidence comes from trials in the specific populations it addresses, because pregnant women, children, and older adults are systematically under-represented in nutrition research. Optimal protein intake in older adults is an active area with recommendations still moving.

👉 Next: the playbook.