Diet and Nutrition

Topics …

• 2.1 A balanced diet
• 2.2 Nutrition    
• 2.3 Hydration
• 2.4 Weight management
• 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

2.1     A balanced diet 

A balanced diet should include:

• Whole foods – colourful fruits and vegetables
• Lean proteins – fish, poultry, tofu and beans
• Healthy fats – olive oil, nuts and seeds
• Fibre-rich foods for digestion and stable blood sugar
• Foods that contain probiotics and probiotics
• Antioxidants that protect cells from damage and slow down aging
• 6-8 glasses of fluid per day – for energy, focus and cellular function.
• Limit added sugars and highly processed foods

Personal story – lacking whole foods:

The consequences of the wrong balance

Carbohydrates – including sugars, bread, pasta, rice, starches and fruit – are an important source of readily available energy. They also support brain function, physical activity, and overall metabolic health. However, regularly consuming more carbohydrates than your body needs in the short term can contribute to problems such as unwanted weight gain and, over time, an increased risk of developing type 2 diabetes (see 2.4 Weight Management below).

The right quantity of carbohydrates depends on your metabolism, your activity level, and your overall energy needs. Whatever the right quantity is, it is balance that matters – the balance between the amount of food you consume and the amount of energy you expend. When these two are out of alignment for long periods, health problems can develop regardless of the specific foods consumed.

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

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.

Vitamin B6 excess:

The symptoms described in the story above about a B12 deficiency can also be the result of too much vitamin B6. This can be caused by supplements that may not appear to contain B6, so it’s always wise to check carefully what supplements contain. Many supplements don’t make this obvious, and small amounts can add up when people take several products at once. Because B6 can cause nerve problems when taken regularly, even at doses that seem low, it’s important to check every label, including products taken for unrelated reasons such as magnesium, immune support, energy, stress, or even B12. Guidelines as to what constitutes a safe amount 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.

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
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
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

2.3     Hydration

Maintaining adequate fluid levels is critically important to support the functioning of our cells, temperature regulation and energy levels. Even mild dehydration can affect mood, focus and physical performance. Severe hydration can be fatal.

During exercise, illness and hot weather, it is also important to ensure you include electrolytes – minerals like sodium, potassium and magnesium that help regulate fluid balance, nerve signals and muscle function.

2.4     Weight management

As mentioned above, regularly eating more carbohydrates than your body can use in the very short term – through daily activity and exercise – can contribute to problems such as unwanted weight gain and, over time, an increased risk of type 2 diabetes. Understanding how this works, and the role of insulin (below), helps illustrate why the balance between food intake and energy expenditure is so important.

The role of insulin, putting on weight and diabetes

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

Insulin also sends a signal to the body to store energy and temporarily reduce fat‑burning. In other words, it promotes fat storage and suppresses fat release, which is why ongoing high insulin levels can make weight loss more difficult. And 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 more insulin.

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

Visceral fat – lean doesn’t mean healthy

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. On the other hand, it can appear as a “beer belly”.

Unlike subcutaneous fat, visceral fat releases inflammatory substances and hormones that can disrupt insulin sensitivity, blood pressure and cholesterol. It can directly affect liver function and increase 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

A sedentary lifestyle and/or genetic make-up can result in visceral fat accumulation and can affect people despite appearing to be trim and healthy.

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 – dealing with visceral fat:

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. A follow-up scan revealed elevated visceral fat. He was stunned. He didn’t eat fast food, didn’t drink excessively and exercised regularly. But his diet was high in refined carbs – white bread, pasta, and energy bars – and low in fibre and healthy fats.

2.5      The importance of your microbiome

“Microbiome” refers to the trillions of bacteria, fungi and other microbes living in your digestive tract that have a critically important role to play in supporting the gut by producing compounds that keep the gut lining healthy and functioning well. It plays a crucial role in your health, as you will see from the table below.

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

What mitochondria need

• regular weight-bearing exercises to make the mitochondria stronger and reasonably vigorous aerobic exercises that multiply the number of mitochondria;
• antioxidant rich foods such as berries, leafy greens and nuts;
• foods containing nutrients – magnesium and B vitamins; and
• good quality, consistent sleep.

What mitochondria don’t need

• chronic stress;
• processed foods and excess sugar;
• sedentary lifestyle and poor sleep; and
• environmental toxins.

Nutrients and food sources for mitochondria

• Many vitamins that are classified as “B” support the chemical reactions that the mitochondria use to produce energy.
• Whole foods that contain the nutrients that mitochondria need include spinach; salmon; beef; eggs; whole grains; legumes; nuts and broccoli.

2.7     How diet helps manage stress

Staying hydrated and maintaining steady blood sugar levels through balanced meals also helps prevent irritability and fatigue, making it easier to cope with daily challenges.

Foods rich in antioxidants are also important for managing the effects of stress and neutralising the effect of excessive free radicals – see below: section 2.10 Free radicals and antioxidants).

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 and put it down to 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 cultivating mindfulness and fostering positive thinking mainly because the nutrients we consume have a direct effect on how the brain functions:

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

Food for thought

Mindful eating isn’t just about what you eat – it’s about how you eat. Slowing down, savouring flavours and textures can improve digestion and, at the same time, reduce stress.

Mood-boosting meals

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

2.9   How diet helps manage cholesterol, hypertension and heart disease

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 (5 or fewer servings per week)
• Processed snacks such as chips and sweetened cereals
• Excess salt (no more than 2300 mg per day)

Foods to include:

• 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 soy milk without sugar
• Lean meats, skinless poultry and fish (limited servings)
• Nuts, seeds and legumes several times per week
• Healthy fats like olive oil and avocado.

DASH Diet

The DASH diet (Dietary Approaches to Stop Hypertension) was developed to prevent and control high blood pressure. It emphasizes plenty of fruits, vegetables, whole grains and low-fat dairy, along with lean proteins like fish and poultry. It limits saturated fats, red meat, sweets and 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 energy production, your immune system and the regulation of processes such as inflammation and blood flow, so they aren’t “bad” per se.

But they are dangerous when they get out of balance, particularly for the brain. That’s where antioxidants come in – they keep the free radicals in balance.

The reason that free radicals are dangerous is because they have an extra electron which makes them unstable. In order to stabilise themselves, they steal an electron from the nearest molecule. This damages the molecule they steal from, turns that molecule into a new free radical and starts a chain reaction. They can even result in mutations in your DNA and the oxidative stress that is caused is a major contributor to neurodegenerative diseases.

Antioxidants stabilise free radicals by donating an electron which pairs with the extra free radical electron. They also help protect the brain by reducing inflammation (which accelerates brain ageing); supporting mitochondria; protecting memory and focus; and slowing long-term cognitive decline.

Foods that are rich in antioxidants include berries; leafy greens; nuts and seeds; dark chocolate; green tea; colourful vegetables and some spices (turmeric and cinnamon).