Nutrition for Adults

Why Nutrition Matters for Adults

For adults between 25 and 65, nutrition shifts from a growth priority to a maintenance and disease-prevention priority. Metabolic health begins to decline as early as the mid-thirties, and dietary choices made during these decades are the single most modifiable factor in determining healthspan, the number of years lived in good health, free of chronic disease.

A 2022 meta-analysis in PLOS Medicine estimated that shifting from a typical Western diet to an optimised diet at age 20 could add approximately 10 years of life expectancy, and even making the change at age 60 could add roughly 8 years.

The Mediterranean Diet: Gold Standard Evidence

No dietary pattern has been more rigorously studied for long-term health outcomes than the Mediterranean diet. Its evidence base spans decades of large-scale prospective studies.

• The landmark PREDIMED trial (7,447 participants) demonstrated a 30% reduction in major cardiovascular events with a Mediterranean diet supplemented with extra-virgin olive oil or nuts
• A 2023 meta-analysis of 29 studies found that high adherence to the Mediterranean diet was associated with 23% lower all-cause mortality
• The diet emphasises extra-virgin olive oil, vegetables, fruits, legumes, nuts, whole grains, fish, and moderate red wine, while limiting red meat, processed foods, and added sugars
• Polyphenols in olive oil, red wine, and colourful vegetables provide potent anti-inflammatory and antioxidant effects at the cellular level

Glucose Tracking & Metabolic Monitoring

Metabolic health is now understood to be far more individual than previously assumed. Two people eating the identical meal can have dramatically different blood glucose responses, influenced by their microbiome, genetics, sleep, stress, and meal timing.

• A pioneering 2015 study in Cell tracked 800 participants and found highly variable glycaemic responses to identical foods, upending the idea that glycaemic index is universal
• Postprandial glucose spikes above 140 mg/dL are associated with increased oxidative stress, endothelial damage, and long-term cardiovascular risk, even in non-diabetic individuals
• Only 12% of American adults are considered metabolically healthy by all five criteria (blood glucose, triglycerides, HDL cholesterol, blood pressure, and waist circumference)
• Many longevity-focused adults are now using continuous glucose monitors to understand their unique metabolic responses. CGMs, ketone meters, and other health tracking devices are available at Healthspan.mu

Intermittent Fasting & Time-Restricted Eating

Time-restricted eating has emerged as one of the most studied dietary interventions for metabolic health in adults.

• A 2023 systematic review in the New England Journal of Medicine confirmed that intermittent fasting improves insulin sensitivity, blood pressure, and markers of oxidative stress
• Time-restricted eating (typically 16:8 or 14:10) has been shown to reduce body weight by 3-8% over 8-12 weeks without deliberate calorie counting
• Fasting periods activate autophagy, the cellular "housekeeping" process that clears damaged proteins and dysfunctional organelles, a key mechanism in longevity research
• The benefits appear to be partly independent of weight loss, suggesting that meal timing itself influences metabolic pathways
• Caution: Intermittent fasting is not appropriate for pregnant or breastfeeding women, individuals with a history of eating disorders, or those taking medications that require food at specific times

Protein Adequacy

Most adults significantly underestimate their optimal protein intake, particularly after age 30 when muscle protein synthesis begins to decline.

• The RDA of 0.8 g/kg/day is increasingly viewed as a minimum to prevent deficiency, not an optimum for health. Leading researchers now recommend 1.2-1.6 g/kg/day for healthy adults
• Higher protein intake is associated with better weight management, greater satiety, and preservation of lean muscle mass during caloric restriction
• A 2020 meta-analysis found that each 10 g/day increase in protein intake was associated with a 12% lower risk of hip fracture
• Distributing protein evenly across meals (25-40 g per meal) is more effective for muscle protein synthesis than consuming the majority at dinner, as most adults do
• Leucine, an essential amino acid abundant in animal proteins, eggs, and dairy, is the primary trigger for muscle protein synthesis. Each meal should contain approximately 2.5-3 g of leucine to maximally stimulate this process

Anti-Inflammatory Eating

Chronic low-grade inflammation, sometimes called "inflammaging," is now recognised as a root driver of nearly every major age-related disease.

• The Dietary Inflammatory Index (DII) has been validated across over 40 studies. A pro-inflammatory diet is associated with higher risks of cardiovascular disease, cancer, depression, and all-cause mortality
• Anti-inflammatory foods: fatty fish (salmon, sardines, mackerel), leafy greens, berries, turmeric, ginger, extra-virgin olive oil, walnuts, and green tea
• Pro-inflammatory foods to limit: refined sugars, trans fats, processed meats, excessive omega-6 seed oils, and ultra-processed snack foods
• A 2021 study in the Journal of the American College of Cardiology found that participants with the most anti-inflammatory diets had a 46% lower risk of heart disease and a 31% lower risk of cancer compared to those with the most pro-inflammatory diets
• Optimising the omega-6 to omega-3 ratio (ideally below 4:1, versus the typical Western ratio of 15-20:1) is one of the most impactful single dietary changes for reducing systemic inflammation