Diet and Nutrition

Topics …

• 2.1 A balanced diet
• 2.2 Nutrition    
• 2.3 Hydration
• 2.4 Weight, insulin, leaky gut and visceral fat
• 2.5 The importance of your microbiome
• 2.6 The importance of your mitochondria
• 2.7 How diet helps manage stress
• 2.8 Diet – brain benefits
• 2.9 Diet – cardiovascular benefits
• 2.10 Free radicals and antioxidants
• 2.11 Blood sugar regulation and glycaemic load
• 2.12 Ultra processed foods

2.1     A balanced diet 

A balanced diet should include:

• Whole foods – fruits, vegetables, legumes, whole grains, nuts, seeds, lean proteins and healthy fats. Whole foods simply means foods that are minimally processed and close to their natural form.
• Fibre‑rich foods – support digestion, stabilise blood sugar and nourish the gut.
• A wide variety of foods – promote a diverse and healthy microbiome, including probiotics (yogurt, kefir, fermented foods) and prebiotics (oats, legumes, onions, garlic).
• Foods rich in antioxidants – help protect cells, especially brain cells, from premature ageing.
• Healthy fats – particularly omega‑3 fats from fish, nuts and seeds, support brain health, reduce inflammation and help the body absorb essential vitamins (A, D, E and K).
• Lean proteins – fish, poultry, tofu and beans.

It is also important to limit highly processed foods. Keep in mind that the human body evolved over a long period of time when there were no fast or processed foods. The prevalence of these in the 21st century is part of the reason that so many people have health problems.

Adjusting diet as we age

It is important to recognise that the right foods, proportions and quantities change as we age and vary from person to person. Genetics, medical conditions, medications and gut health all influence how different foods affect each person, which is why listening to your body is an important part of a balanced diet.

As we reach our 60s and 70s, our metabolism naturally slows, making weight gain more likely unless dietary intake is adjusted. At the same time, the body becomes less efficient at absorbing certain nutrients – particularly vitamin B12, calcium and vitamin D – meaning some people may need to be more deliberate about their food choices to maintain adequate nutrition.

Protein needs also increase with age. Older adults require more protein to maintain muscle strength, mobility and immune function, because the body becomes less efficient at using dietary protein and muscle mass naturally declines. In more advanced cases, this can progress to sarcopenia, a condition characterised by significant muscle loss, reduced strength and impaired physical performance which increases the risk of falls.

These changes – slower metabolism, reduced nutrient absorption and higher protein requirements – can all contribute to weight gain. The most effective response is to maintain or increase physical activity so that energy intake and energy expenditure remain in balance.

Ideally, each person should seek advice from a qualified nutritionist to determine the best diet for their individual needs. However, most people do not do this, so the following provides general guidance. More detailed suggestions for each stage of life can be found in the age‑specific sections (20s; 30s; 40s; 50s; 60s; 70s; 80s and 90s).

Personal story – lacking whole foods

General suggestions for a balanced diet

• Eat a variety of colourful fruits and vegetables daily
• Include whole grains and legumes for fibre and sustained energy
• Choose lean proteins such as fish, poultry, tofu and beans
• Use healthy fats such as olive oil, nuts and seeds
• Limit added sugars and highly processed foods
• Practise mindful eating and avoid skipping meals
• Maintain consistent meal timing to support metabolic stability

Affordable food

2.2 Nutrition

“Resilience” in this context means the body’s ability to adapt, recover from illness and injury, and function effectively when under stress and/or as you age. A resilient metabolism can adjust to changes in food intake, regulate blood sugar, and maintain energy balance. Further reading: Food to build resilience.

Even mild deficiencies in nutrients such as iron, vitamin B12, magnesium or vitamin D can cause fatigue, mood changes, reduced immunity and impaired cognitive function long before more serious symptoms appear. Adequate protein intake is also essential for maintaining muscle mass, supporting metabolic health and preserving strength as we age.

Personal story – iron deficiency

Sometimes we have to be patient when our system is out of kilter – far better to be proactive by having the right diet in first place.

Personal story – B12 deficiency:

BH, a 60-year-old woman, had numbness and tingling in her hands and feet. A blood test confirmed vitamin B12 deficiency. She adjusted her diet to include more B12 sources like eggs, dairy and fortified cereals. After six months, the numbness and tingling disappeared.

It’s interesting that those particular symptoms can also be caused by nerve damage from too much vitamin B6. This can occur through supplements that may not appear to contain B6, so it’s always wise to check all supplement labels carefully. Guidelines as to what constitutes a safe amount of B6 vary, and are in the process of change, so it’s important to check current guidelines before you consume B6 without medical advice.

Personal story – vitamin D deficiency

AF, a 45-year-old woman, experienced chronic fatigue and frequent colds. Blood tests revealed a severe vitamin D deficiency. After incorporating vitamin D-rich foods like fatty fish, fortified dairy, and increased safe sun exposure, her energy levels improved markedly within three months. Vitamin D deficiency is extremely common, especially in people who work indoors or live in areas with limited sun exposure.

Key nutrients, recommended intake, food sources and benefits

The following table lists key nutrients, their recommended daily intake, common food sources and their benefits:

Nutrient	Adult daily intake	Common food sources	Age-specific notes	Benefits
Calcium	1,000-1,300 mg	Dairy, tofu, leafy greens, fortified plant milks	Upper end of the range for women 50+ and men 70+	Builds strong bones, supports nerve and muscle function
Choline	425–550 mg	Eggs, fish, legumes, meat	Needs increase during pregnancy; many adults don’t have enough	Supports brain function, liver health, and metabolism
CoQ10	100-200 mg	Organ meats, fatty fish, spinach	Body production declines with age;	Powers cellular energy, protects mitochondria, supports heart health
Fibre	25-30 g	Vegetables, legumes, whole grains, fruits	Needs consistent intake across all ages	Supports gut health, reduces inflammation, improves digestion
Iron	8-18 mg	Red meat, lentils, fortified cereals	Menstruating women need more; excess can be harmful	Carries oxygen in blood, supports energy and immune function
Magnesium	310-420 mg	Nuts, legumes, whole grains, spinach	Absorption may decline with age;	Supports energy production, muscle function, and mood regulation
Olive Oil	~2-4 tablespoons	Extra virgin olive oil	Use as primary cooking fat	Anti-inflammatory, supports cardiovascular and cognitive health
Omega-3s (EPA/DHA)	250-500 mg combined	Fatty fish (salmon, sardines), flaxseeds, walnuts	Older adults may benefit from higher doses for heart and brain support	Supports brain function, reduces inflammation, protects heart health
Potassium	2,600–3,400 mg	Fruits, vegetables, legumes, potatoes	Important for blood pressure control; needs increase with age	Regulates blood pressure, supports nerve and muscle function
Protein	1-1.2 g per kg body wgt	Eggs, fish, legumes, lean meats, dairy	Older adults may need more to preserve muscle	Preserves muscle mass, supports brain function and metabolic health
Vitamin B12	2.4 µg	Eggs, dairy, meat, fortified cereals	Absorption declines with age; supplements may be needed after 50	Supports nerve health, red blood cell formation, and cognition
Vitamin D	600-800 IU (15–20 µg)	Sunlight, fatty fish, fortified foods	Older adults may need 800–1,000 IU/day; check with GP	Supports bone health, immunity, and mood stability
Zinc	8-11 mg	Meat, seafood, legumes, nuts	Absorption declines with age	Supports immunity, wound healing, and metabolism

Nutrient interactions

Nutrients often work together. For example, vitamin D helps the body absorb calcium; vitamin C improves iron absorption; magnesium supports vitamin D activation; and vitamin K2 helps direct calcium into bones rather than arteries. Understanding these interactions helps ensure your diet supports your whole system, not just individual nutrients.

Supplements

A balanced diet should normally provide the nutrients that are needed by our bodies. But sometimes nutrient deficiencies do occur so, if a deficiency is indicated by a blood test, or when the absorption of nutrients declines with age, supplements can be helpful. Common examples include vitamin B12, vitamin D, magnesium and omega‑3s.

Supplements should be used carefully, as excessive doses of certain nutrients – such as vitamin B6 or iron – can be harmful.

Signs of a possible deficiency

If you experience persistent fatigue, low mood, tingling, muscle cramps, poor sleep or frequent infections, it may be worth asking your GP for blood tests. Common tests include:

• Iron studies
• Vitamin B12
• Vitamin D
• Magnesium
• Thyroid function

Identifying deficiencies early can prevent long‑term health problems.

2.3     Hydration

Maintaining adequate fluid levels is critically important for overall health. Water supports every major bodily function – including the functioning of our cells, temperature regulation, blood pressure, digestion and energy levels. Even mild dehydration can affect mood, concentration and physical performance. Severe dehydration can be life‑threatening.

During exercise, illness or hot weather, it is also important to replace electrolytes – minerals such as sodium, potassium and magnesium – that regulate fluid balance, nerve signalling and muscle function. Without adequate electrolytes, drinking water alone may not fully restore hydration, and symptoms such as muscle cramps, dizziness or fatigue can occur.

2.4     Weight, insulin, leaky gut and visceral fat

Carbohydrate imbalance

Regularly eating more carbohydrates than your body can use in the short term – through daily activities and exercise – can cause unwanted weight gain and, over time, an increased risk of type 2 diabetes and other health problems.

For example, post‑meal glucose spikes that are exacerbated by too many carbohydrates, especially refined carbohydrates, force the pancreas to release more insulin. Over time, this pattern contributes to chronically elevated insulin levels and reduced insulin sensitivity. This is part of the reason why the balance between food intake and energy expenditure is so important.

Dieting

Repeated calorie‑restrictive diets can also cause the body to lower its metabolic rate to conserve energy. This “metabolic slowdown” is one reason why people often regain weight after dieting – the body becomes more efficient at storing fat and less efficient at burning it. Proactive habits avoid this trap.

Calorie restriction can also result in an increase in cortisol that can aggravate gut permeability and therefore weight management (see Leaky Gut below).

The role of insulin, putting on weight and diabetes

Insulin is the hormone that helps move sugar from your bloodstream into your cells. When you eat, your blood sugar rises and your pancreas releases insulin to bring it back down by moving glucose into your cells.

Eating too much – especially carbohydrates – results in more insulin being released and more sugar being stored in your cells. Insulin also sends a signal to the body to convert excess glucose into fat and to temporarily reduce fat‑burning, thereby preventing fat from being released. This is why ongoing high insulin levels can make weight loss more difficult.

It can become a vicious cycle – high insulin levels can cause your body to become less responsive to insulin (exacerbated by ageing, inactivity and excess weight). The pancreas then compensates for the lack of responsiveness by producing even more insulin, so more fat is stored.

Over time, this can lead to higher hunger levels, weight gain and, eventually, insulin resistance. The end result can be type 2 diabetes.

More information can be found about insulin, blood sugar management and glycaemic index in section 2.12 below

Leaky gut

Research indicates that poor diet (especially highly processed foods), stress, poor sleep and medications such as anti-inflammatories can cause the gut lining to become more permeable than it should be. This can result in tiny fragments of gut bacteria entering the bloodstream and triggering inflammation.

This inflammation interferes with the way the hypothalamus – the part of the brain that regulates hunger and metabolism – responds to hormones like leptin that normally tell the body that it’s had enough food. When this signalling is disrupted, the brain responds as though the body is low on energy, increasing appetite and reducing metabolic rate – a nightmare for weight regulation.

Gut inflammation can also interfere with the vagus nerve, the communication pathway between the gut and the brain, and reduce the release of GLP‑1, a hormone that helps regulate appetite and blood sugar. This is the same pathway targeted by medications such as semaglutide.

Supporting gut health with a balanced diet (2.1 above), good sleep and stress management can help the body regulate appetite, energy use and weight management.

Muscle mass and weight regulation

Muscle mass plays a major role in weight regulation. Muscle tissue burns more energy than fat, even at rest. As we age, natural muscle decline reduces metabolic rate, making weight gain more likely unless strength‑building activity is maintained.

Sleep, circadian rhythm and weight

Poor sleep disrupts hormones that regulate appetite – increasing ghrelin (hunger) and reducing leptin (satiety). Circadian rhythm disruption also affects insulin sensitivity, making weight regulation harder. This is why consistent sleep patterns are essential for metabolic stability.

Stress, cortisol and weight

Chronic stress increases cortisol, which can raise blood sugar, increase appetite and promote fat storage – particularly visceral fat. Managing stress is therefore a key part of weight regulation.

Visceral fat

Visceral fat wraps around vital organs such as the liver, pancreas and intestines. It is not always visible and can be present even in people with flat bellies and low body fat percentages, although it can also cause “beer belly”.

Unlike subcutaneous fat, visceral fat releases inflammatory substances and hormones that can disrupt insulin sensitivity, blood pressure and cholesterol. It is closely linked to fat accumulation in the liver, which can impair metabolic function. Visceral fat increases the risk of cardiovascular disease, type 2 diabetes and certain cancers. Further reading: Why visceral fat is dangerous

Who is at risk and how to identify if you have it

You may also want to ask your doctor about the benefits of semaglutide (a weight loss drug often sold as Ozempic) for the reduction of visceral fat, although a large percentage of those people who lose weight using such drugs subsequently put the weight back on.

Interestingly, a study conducted in 2025 of 17,604 people by University College London found that semaglutide was also effective for reducing the risk of heart disease (a 20% reduction compared to the other half of the test group who were on a placebo).

Personal story – slim doesn’t mean safe

TY was a lean, active accountant (53yo) who cycled on weekends and did not appear to be overweight. But, during a corporate wellness screening, his waist circumference flagged concern.

Weight set-point

The body has a “weight set‑point” – a range it tries to maintain. Poor sleep, stress, gut inflammation and chronically elevated insulin can push this set‑point higher. Proactive health habits help bring the set‑point back down over time by restoring appetite regulation, metabolic flexibility and hormonal balance.

Conclusion

The most effective approach to weight management is not dieting, but restoring the systems that regulate appetite, metabolism and energy use – including gut health, sleep, stress management, muscle strength and balanced nutrition. When these systems work well, weight tends to regulate itself naturally.

2.5      The importance of your microbiome

“Microbiome” refers to the trillions of bacteria, fungi and other microbes living in your digestive tract. These microbes form a complex ecosystem that plays a crucial role in your health, influencing everything from digestion and immunity to mood, metabolism and even cancer risk.

A healthy microbiome is diverse, meaning it contains many different species of beneficial microbes. This is important – diversity is one of the strongest predictors of long‑term health.

Area of health	The role of the microbiome	Why it matters
Cardiovascular system	Helps regulate cholesterol and blood pressure	Reduction of cholesterol and blood pressure helps prevent heart disease and stroke
Digestive system	Helps to break down food, producing enzymes, and absorbing nutrients	Reduces bloating and improves the absorption of nutrients; helps with regularity
Hormone balance	Enables absorption of nutrients like zinc, magnesium and B vitamins needed for hormone balance	Influences stress response, metabolism and menstrual health
Immune system	It teaches immune cells what to attack, regulates inflammation and helps to keep out dangerous germs	Helps prevent infections, allergies, autoimmune conditions and even cancer (see below)
Mental health (see section 4.4)	About 95% of the body’s serotonin – a key emotional and mood stabiliser – is made in the gut and communicated to the brain	Affects mood, anxiety, cognition and sleep quality as explained in section 4.5 The link between your microbiome and your brain
Metabolic health	Influences insulin sensitivity, fat storage and energy balance	Affects weight, blood sugar, and risk of Type 2 diabetes
Skin health	Modulates inflammation and nutrient absorption	Impacts acne, eczema, and skin barrier function

Your microbiome, your immune system and cancer

How to nourish your gut microbiome

On the other hand, prebiotics are the fermentable fibres that feed your existing gut bacteria. They aren’t actually digested – they pass through to the large intestine, where they provide fuel for the microbes that support immune function, gut barrier integrity and metabolic health. Good prebiotic sources include onions, garlic, leeks, asparagus, oats, legumes, and resistant starch from cooked‑and‑cooled potatoes or rice.

Together, probiotics and prebiotics work synergistically to support a healthy microbiome. If you’re not eating fermented foods regularly, a probiotic supplement is worth considering e.g. it has been shown by various trials to improve cognitive function. Further reading: The effect of probiotics on brain functioning.

What to avoid

For example, in one case, a girl in her early teens was prescribed antibiotics 12 times over 18 months and developed chronic depression, which she had for 17 years. Although there is no scientific evidence that the antibiotics actually caused her depression, that is thought to be most likely candidate. In 2017, a faecal microbiota transplant restored the balance in her gut. Her depression disappeared. At the time of writing, it has not returned.

Personal story – the importance of diversity

DP, aged 51, considered himself health conscious. He avoided fast food, cooked most of his meals and ate healthy food – mainly grilled chicken, brown rice and steamed broccoli. Despite this, he often felt bloated, sluggish and had too many minor problems such as colds. A friend mentioned the importance of the microbiome to him, so he started reading about it and realised his diet lacked diversity, especially plant fibres and fermented foods. He started small – adding purple cabbage, leeks and lentils to his meals. He then tried fermented food (kefir and kimchi) and properly fermented sauerkraut. Within weeks, his digestion improved. Within months, his energy returned, his mood improved and even had clearer skin. He now ensures that he always has colourful and diverse food, and he includes both probiotics and prebiotics in his diet.

2.6     The importance of your mitochondria

We know that the more mitochondria you have, and the stronger they are, the more energy your body can produce. This tends to put the focus on energy, but strong, efficient mitochondria play a critical role in good physical and mental health in general. For example, when mitochondria are under stress – when something interferes with their ability to produce ATP efficiently (see “What mitochondria don’t need” below) – they produce inflammation. Strengthening your mitochondria reduces inflammation throughout the body and promotes immunity and longevity.

Healthy mitochondria also support clearer thinking, better memory, improved mood and reduced risk of cognitive decline.

What mitochondria need

• regular physical activity including strength-building exercises to make your mitochondria stronger and reasonably vigorous aerobic exercises to increase the number of mitochondria (see 3.4 Exercise and your mitochondria);
• movement throughout the day, not just structured exercise – long periods of sitting reduce mitochondrial efficiency;
• antioxidant rich foods such as berries, leafy greens and nuts;
• nutrients essential for mitochondrial energy production, especially magnesium and B vitamins; and
• good quality, consistent sleep that allows mitochondria to repair and regenerate.

What mitochondria don’t need

• processed foods and excess sugar which increase inflammation and oxidative stress;
• physical inactivity – e.g. long periods of sitting – and poor sleep, both of which reduce mitochondrial number and efficiency;
• chronic stress and inflammation which increase cortisol and damage mitochondrial function; and
• environmental toxins, including cigarette smoke and pollutants, which impair mitochondrial energy production.

Nutrients and food sources for mitochondria

The chemical energy that is extracted from food needs to be converted into a form that can be used by us. This is achieved by our mitochondria which convert chemical energy into ATP (adenosine triphosphate).  B vitamins and magnesium are needed for this process. Whole foods that contain the necessary nutrients include:

• spinach
• salmon
• beef
• eggs
• whole grains
• legumes
• nuts
• broccoli

2.7     How diet helps manage stress

Foods rich in antioxidants – such as berries; leafy greens; nuts and seeds; colourful vegetables; etc – also help manage stress by neutralising excessive free radicals, which can cause cellular damage as explained in section 2.10 below Free radicals and antioxidants), and by reducing inflammation, which is closely linked to stress.

Other foods that also support stress management by lowering inflammation include oily fish such as salmon and sardines (rich in omega‑3 fatty acids), flaxseeds, walnuts and fermented foods.

A balanced diet will help maintain steady blood sugar levels which helps prevent irritability, energy crashes and difficulty concentrating. When blood sugar fluctuates sharply, the body releases adrenaline and cortisol – the same hormones that are involved in stress – which can make daily challenges feel harder to manage.

Similarly, dehydration can increase cortisol, reduce cognitive performance and worsen mood. Staying hydrated and maintaining steady blood sugar levels through balanced meals helps prevent irritability and fatigue, making it easier to cope with daily challenges.

Further reading: Food to reduce anxiety.

Personal story – diet and stress

PJ, a dedicated project manager in her early 40s, was juggling tight deadlines in a demanding job. She also had the added pressure of caring for her aging parents. Her meals became an afterthought – coffee for breakfast, fast food snacks between meetings and takeaway for dinner while replying to emails. She was undernourished. She started experiencing chronic stress symptoms, including poor sleep, which she assumed was simply burnout.

Fortunately, when she visited her GP, he asked about her diet and, as a result, she started working with a nutritionist who helped her rebuild her meals around whole foods – slow-digesting carbs, leafy greens, nuts, seeds and magnesium-rich vegetables. She added omega-3s through chia seeds and salmon. She gave up a couple of cups of coffee a day and switched to herbal tea. Within weeks, her sleep improved. Within months, her stress level was manageable.

2.8     How diet helps mindfulness and positive thinking

A well‑balanced diet plays an important role in supporting brain function, emotional stability and mindfulness. The nutrients we consume directly influence how the brain produces energy, communicates through neurotransmitters and regulates mood.

When the brain is well‑nourished, it becomes easier to think clearly, stay present, manage emotions and maintain a positive outlook. When it is under‑nourished – especially through diets high in processed foods, sugar or caffeine – mood swings, anxiety, irritability and poor concentration become more likely.

Nutrient	Common Sources	Cognitive & Emotional Benefits
Amino Acids (e.g., tryptophan, tyrosine)	Turkey, tofu, dairy, bananas	Building blocks for serotonin and dopamine, important mood chemicals
Antioxidants (Vitamin C, E, polyphenols)	Berries, citrus fruits, green tea	Protects brain cells, improves focus, slows cognitive decline
B Vitamins (especially B6, B9, B12)	Leafy greens, legumes, eggs, fortified cereals	Enhances energy metabolism, reduces brain fog, supports emotional balance
Magnesium	Pumpkin seeds, spinach, dark chocolate	Calms the nervous system, aids sleep, reduces anxiety
Omega-3 Fatty Acids	Fatty fish (salmon, sardines), flaxseeds, walnuts	Supports memory, reduces inflammation, stabilizes mood
Protein	Eggs, fish, legumes, lean meats, dairy	Supports general brain functioning

These nutrients help the brain regulate mood, maintain attention, support memory and respond appropriately to stress.

Food for thought

Food for thought

Mindful eating isn’t just about what you eat – it’s also about how you eat. Slowing down, noticing flavours and textures, and eating without distraction improves digestion and helps regulate appetite. It also reduces stress by activating the parasympathetic (“rest and digest”) nervous system.

Mood-boosting meals

Here are a few examples of meals that include brain-supportive nutrients: Further reading: Brain boosting food.

Snack: Greek yogurt with chia seeds and sliced banana – supports gut health and provides sustained energy.

These meals stabilise blood sugar, reduce inflammation and support neurotransmitter production – all essential for emotional stability and positive thinking.

2.9   How diet helps manage cholesterol, hypertension and heart disease

It’s important to have a diet with minimum saturated and trans fats, which increase LDL cholesterol (the type that contributes to plaque buildup); promote inflammation (a major driver of cardiovascular disease) and impair blood‑vessel flexibility.

Foods and drinks to avoid or limit

• Fried foods and fast food (often high in unhealthy fats)
• Processed meats like salami, sausages, and deli meats
• Baked goods such as cakes, pastries and biscuits containing trans fats
• High-fat dairy products like butter, cream and full-fat cheese
• Fatty cuts of red meat
• Milk chocolate and other chocolate with added sugars
• Sugary drinks like sodas and sweetened juices
• Sweets and candies (limit to 5 or fewer servings per week)
• Processed snacks such as chips and sweetened cereals
• Excess salt (no more than 2300 mg per day, ideally closer to 1,500 mg). High salt intake raises blood pressure by increasing fluid retention and placing extra strain on blood vessels. Reducing salt is one of the fastest ways to improve blood pressure.)

Foods to include

These foods actively support heart health:

• Fruits and vegetables rich in fibre (4-5 servings of each per day)
• Whole grains – oats, barley and brown rice (6-8 daily servings)
• Low-fat dairy (2-4 daily servings) or unsweetened soy milk
• Lean meats and skinless poultry (limited servings)
• Nuts, seeds and legumes several times per week
• Healthy fats like olive oil and avocado
• Fatty fish (salmon, sardines, mackerel) for omega 3s that reduce inflammation and support heart rhythm stability
• Plant sterols (found in fortified spreads, nuts and seeds) which help lower LDL cholesterol
• Potassium rich foods (bananas, potatoes, beans, leafy greens) which help counteract sodium and lower blood pressure
• Soluble fibre – found in oats, barley, beans, apples and citrus fruits – is particularly effective at lowering LDL cholesterol..

DASH Diet

The DASH diet (Dietary Approaches to Stop Hypertension) was developed to prevent and control high blood pressure. It emphasizes:

• fruits
• vegetables
• whole grains
• low‑fat dairy
• lean proteins like fish and poultry

It limits:

• saturated fats
• red meat
• sweets
• sugary drinks

The DASH diet helps lower blood pressure and LDL cholesterol, supporting overall heart health. It shares similarities with the Mediterranean diet but does not focus on olive oil or wine.

2.10 Free radicals and antioxidants

Free radicals are tiny unstable molecules created by a range of bodily processes – breathing, thinking, moving, digesting food, and dealing with stress. They are a necessary part of life and play an important role in energy production, your immune system and the regulation of processes such as inflammation and blood flow, so they aren’t “bad” per se.

However, free radicals become dangerous when they increase beyond our needs. This imbalance is known as oxidative stress, and it is particularly harmful for the brain, which is highly sensitive to oxidative damage. Oxidative stress also plays a major role in cardiovascular disease, diabetes, chronic inflammation and reduced immune function.

This is why antioxidants are important – their role is to keep the free radicals in balance (more about this below).

Why free radicals can be harmful

The reason that free radicals are dangerous is because they have an extra electron which makes them unstable. For stability, they steal an electron from the nearest molecule. This damages the molecule they steal from, turns the molecule they steal from into a new free radical and triggers a chain reaction.

Over time, excessive free radicals can:

• damage cell membranes
• impair mitochondria
• disrupt neurotransmitters
• accelerate ageing
• cause mutations in DNA
• contribute to neurodegenerative diseases such as Alzheimer’s and Parkinson’s

What causes excessive free radicals

Although free radicals are produced naturally, certain lifestyle factors increase their production:

• chronic stress
• poor diet (especially processed foods and excess sugar)
• smoking
• alcohol
• pollution
• poor sleep
• long‑term inflammation
• excessive sun exposure
• sedentary lifestyle

This is why proactive health habits – diet, sleep, movement and stress management – are so important.

How antioxidants protect you

Antioxidants stabilise free radicals by donating an electron which pairs with the free radical’s unpaired electron and neutralises it. This stops the chain reaction and the damage it causes.

Antioxidants also:

• reduce inflammation (which accelerates ageing and oxidative stress)
• support mitochondria (which are highly vulnerable to free‑radical damage)
• protect memory, focus and long‑term cognitive function
• help maintain healthy blood vessels
• support immune resilience

Your body produces some antioxidants naturally, but many come from food – especially colourful plant foods.

Foods rich in antioxidants

Although free radicals are produced naturally, certain lifestyle factors increase their production:

• berries
• leafy greens
• nuts and seeds
• dark chocolate (high‑cocoa, low‑sugar)
• green tea
• colourful vegetables (capsicum, carrots, tomatoes, beetroot)
• spices such as turmeric and cinnamon
• herbs such as rosemary, oregano and thyme

Eating a wide variety of these foods helps maintain a healthy balance between antioxidants, protecting your cells and supporting long‑term health.

2.11   Blood sugar regulation and glycaemic load

Blood sugar regulation is one of the most important – and most overlooked – aspects of long‑term health. When we eat carbohydrates, they are broken down into glucose, which enters the bloodstream. Some foods such as white bread, rice, pasta, pastries, sweets and sugary drinks (known as high glycaemic foods) cause rapid spikes in blood sugar. The body responds by releasing insulin to bring blood sugar back down (the role of insulin – link – is discussed in more detail in 2.3 Weight Management above).

Over time, repeated spikes can:

• increase inflammatio
• accelerate ageing through glycation
• worsen insulin resistance
• increase appetite and cravings
• reduce metabolic flexibility
• impair blood‑vessel function
• increase cardiovascular risk
• affect mood, energy and cognitive clarity

Low‑glycaemic foods – such as vegetables, legumes, whole grains, nuts, seeds and most fruits – produce a slower, steadier rise in blood sugar, supporting stable energy and reducing stress on the pancreas.

How to reduce glycaemic load

Over time, repeated spikes can:

• Add protein or healthy fats to carbohydrate-rich meals
• Increase fibre intake (especially soluble fibre)
• Avoid sugary drinks
• Limit desserts and sweet snacks
• Eat balanced meals rather than carbohydrate-heavy meals
• Avoid late‑night eating, when insulin sensitivity is lowest.

Managing glycaemic load supports weight regulation, heart health, brain function, stress resilience and mitochondrial efficiency.

2.12   Ultra Processed Foods (UPFs)

Ultra processed foods are industrially manufactured products containing additives, emulsifiers, artificial flavours, stabilisers and refined ingredients. They are designed to be hyper palatable and easy to overconsume.

Common examples of UPFs include:

• packaged snacks
• sweetened cereals
• fast food
• soft drinks
• processed meats
• instant noodles
• commercial baked goods
• many frozen meals

Effect on your health:

• Damage to gut lining and bacteria causing microbiome disruption
• Increased inflammation throughout the body
• Insulin resistance: high sugar and refined starches worsen blood sugar control
• Appetite dysregulation: UPFs interfere with satiety hormones, increasing cravings
• Mitochondrial stress: poor nutrient density reduces energy production
• Cardiovascular risk: UPFs increase LDL cholesterol and blood pressure
• UPFs affect mood, cognition and emotional regulation

Reducing UPFs – even by 20-30% – has measurable benefits for weight, energy, mood, digestion and long-term disease risk.