People often think they're thin because their metabolism is good, or overweight because they have a bad metabolism. But is this truly the case? While metabolism certainly plays a role in our body composition, the relationship is far more nuanced than most realise and more importantly, there's much we can do to influence it positively. 

In this blog, we’ll explore what metabolism is, how to boost it, and how functional nutrition can help enhance it.

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Understanding Metabolism

Metabolism refers to the complex chemical processes that occur within our bodies to maintain life. These biochemical reactions convert the food we eat into the energy needed to power everything we do, from moving to thinking to growing. Far from being a simple calorie-burning furnace, your metabolism is an intricate system that influences virtually every aspect of your health.

A well-functioning metabolism is important not just for weight management but for energy production, immune function, detoxification, and overall vitality. When your metabolic processes are working optimally, you'll likely experience consistent energy levels, better mood stability, improved mental clarity, and yes- a more efficient ability to maintain a healthy weight.

Several factors influence your metabolic rate:

• Age: Metabolism naturally slows as we get older, largely due to hormonal changes and loss of muscle mass.
• Genetics: Your genetic makeup provides a blueprint for your metabolic tendencies, though it's not your destiny.
• Hormone levels: Thyroid hormones, insulin, cortisol, and sex hormones all play crucial roles in regulating metabolism.
• Muscle mass: Muscle tissue requires more energy to maintain than fat tissue, even at rest.
• Lifestyle choices: Diet, physical activity, sleep quality, and stress levels all impact metabolic function.

While some factors like genetics and age are beyond our control, many aspects of metabolism can be positively influenced through functional nutrition and lifestyle strategies.

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The Science of Metabolism

To effectively increase your metabolism, it's essential to understand how it works on a fundamental level. Your overall metabolic rate comprises several components:

Basal Metabolic Rate (BMR)

Your BMR accounts for approximately 60-70% of your total energy expenditure. It represents the number of calories your body needs at complete rest to maintain vital functions like breathing, circulating blood, and cell production. It is like the minimum energy requirement to keep your body functioning whilst doing absolutely nothing.

Factors affecting BMR include:

• Body size and composition (especially muscle mass)
• Age (BMR typically decreases by 1-2% per decade after age 20)
• Sex (men generally have higher BMRs than women due to greater muscle mass)
• Thyroid function
• Nutritional status

Thermic Effect of Food (TEF)

This is the energy your body expends to digest, absorb, and metabolise food nutrients. Different macronutrients have varying thermic effects:

• Protein: 20-30% of calories consumed (highest TEF)
• Carbohydrates: 5-10% of calories consumed
• Fats: 0-3% of calories consumed (lowest TEF)

This means that eating 100 calories of protein requires up to 30 calories just for processing, while 100 calories of fat might require only 3 calories to process.

Physical Activity

This component includes both intentional exercise and non-exercise activity thermogenesis (NEAT). NEAT encompasses all the ways you move throughout the day that aren't deliberate exercise, like fidgeting, standing, walking to the kitchen, typing, and even maintaining posture. For many people, especially those with sedentary jobs, increasing NEAT can be a powerful way to boost metabolism.

Hormonal Regulation

Hormones act as chemical messengers that orchestrate metabolic processes:

• Thyroid hormones regulate the rate at which your cells convert nutrients into energy.
• Insulin directs glucose into cells for energy or storage.
• Cortisol mobilises energy stores in response to stress, but chronically elevated levels can disrupt metabolism.
• Leptin and ghrelin regulate hunger and satiety signals.
• Sex hormones like oestrogen and testosterone influence fat distribution and muscle development.

When these hormones are balanced, metabolism functions optimally. However, factors like chronic stress, poor nutrition, and inadequate sleep can disrupt this delicate balance.

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Functional Nutrition Strategies to Boost Metabolism

From a functional nutrition perspective, metabolism isn't simply "eating less and moving more." Instead, it's about nourishing your body with the right nutrients at the right times to optimise metabolic pathways. Here's how to approach this:

Macronutrient Balance

Protein

Protein has the highest thermic effect of all macronutrients, meaning your body burns more calories digesting protein than it does processing carbohydrates or fats. Additionally, adequate protein intake supports muscle synthesis and preservation, which directly impacts your BMR.

Aim for high-quality protein sources like:

• Fish
• Free-range poultry
• Grass-fed meats
• Legumes and pulses

Most adults benefit from consuming 1.2-2g of protein per kilogram of body weight daily, especially when looking to increase metabolism or maintain muscle mass.

Fats

Contrary to outdated nutritional advice, healthy fats are essential for metabolic health, particularly for hormone production. Your thyroid, sex hormones, and adrenals all require good fats to function properly.

Focus on these metabolism-supporting fats:

• Omega-3 rich sources (wild salmon, mackerel)
• Extra virgin olive oil
• Avocados
• Coconut oil (contains medium-chain triglycerides that may enhance thermogenesis)

Carbohydrates

Not all carbohydrates affect metabolism equally. Complex carbohydrates provide sustained energy and support gut health, which is increasingly recognised as essential for metabolic wellness.

Choose:

• Whole grains like oats, brown rice, and quinoa
• Starchy vegetables like sweet potatoes and butternut squash
• Fibrous vegetables like broccoli, Brussels sprouts, and dark leafy greens
• Low-sugar fruits like berries, apples, and pears

Meal Timing and Frequency

Chrononutrition

This emerging field explores how the timing of food intake affects metabolic health. Research suggests that aligning your eating patterns with your circadian rhythms, your body's internal clock, can optimise metabolism.¹

Practical applications include:

• Eating most of your calories earlier in the day
• Allowing 12-14 hours between dinner and breakfast
• Eating in sync with natural daylight hours when possible

Intermittent Fasting

Various forms of intermittent fasting have shown promise for enhancing metabolic flexibility, like your body's ability to switch between burning carbohydrates and fat for fuel. Common approaches include:

• 16:8 method (16 hours fasting, 8-hour eating window)
• 5:2 method (5 days of normal eating, 2 days of reduced calories)
• Time-restricted eating (limiting food intake to a specific window each day)

These approaches may help increase insulin sensitivity and support mitochondrial health, both crucial for optimal metabolism.

Micronutrient Sufficiency

Several vitamins and minerals serve as essential cofactors in metabolic pathways:

• B vitamins: Required for energy production from food
• Iron: Necessary for oxygen transport, which fuels metabolic processes
• Magnesium: Involved in over 300 enzymatic reactions, many related to metabolism
• Zinc: Important for insulin function and thyroid hormone production
• Selenium: Essential for thyroid function
• Iodine: Required for thyroid hormone synthesis

Functional nutrition practitioners often recommend comprehensive testing to identify specific deficiencies before targeted supplementation.

Hydration

Water is involved in virtually every metabolic process. Even mild dehydration can slow metabolic rate and reduce energy levels. Research shows that drinking 500ml of water can temporarily boost metabolism by 10-30% for about an hour ².

Aim for:

• Minimum 2-3 litres daily
• More if you're active or in hot weather
• Herbal teas and infused water for variety

Lifestyle Interventions

Physical Activity

One of the most powerful ways to boost metabolism long-term is to build muscle mass through resistance training. Muscle tissue is metabolically active, burning more calories at rest than fat tissue.

Recommendations:

• Strength train 2-4 times weekly
• Focus on compound movements (squats, deadlifts, presses)
• Progressive overload (gradually increasing weight/resistance)
• Include all major muscle groups

While not as powerful for long-term metabolic change as resistance training, aerobic exercise increases calorie expenditure during and after activity through the "afterburn effect" (excess post-exercise oxygen consumption).

Effective approaches include:

• High-intensity interval training (HIIT)
• Steady-state cardio (walking, cycling, swimming)
• Combining both methods throughout the week

Sleep Hygiene

Poor sleep dramatically impacts metabolism by:

• Disrupting hunger hormones (increasing ghrelin, decreasing leptin)
• Elevating cortisol and insulin resistance
• Reducing energy for physical activity
• Impairing recovery from exercise

Prioritise 7-9 hours of quality sleep by:

• Maintaining consistent sleep/wake times
• Creating a cool, dark sleeping environment
• Limiting blue light exposure before bed
• Avoiding caffeine after midday

Stress Management

Chronic stress elevates cortisol levels, which can:

• Promote fat storage, especially around the abdomen
• Increase cravings for energy-dense foods
• Impair insulin sensitivity
• Disrupt digestive function
• Interfere with thyroid hormone conversion

Effective stress management techniques include:

• Mindfulness meditation
• Deep breathing exercises
• Regular time in nature and grounding
• Yoga or tai chi
• Setting appropriate boundaries

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iThrive’s Personalised Functional Nutrition Approach

The most effective metabolism-boosting strategy is one tailored by iThrive to your unique biochemistry and lifestyle.

Assessment

We use comprehensive tools to assess metabolic function:

• Metabolic testing (resting metabolic rate)
• Hormone panels (thyroid, adrenal, sex hormones)
• Nutrient status testing
• Food sensitivity identification
• Gut health assessment
• Detailed health history and symptom analysis

Individualisation

Based on assessment findings, interventions might include:

• Specific macronutrient ratios customised to your needs
• Targeted supplementation for identified deficiencies
• Personalised meal timing strategies
• Exercise prescriptions based on hormonal status
• Addressing underlying imbalances or dysfunctions

Monitoring

Metabolism isn't static. It responds to interventions and changes over time. Regular follow-ups allow for adjustments based on:

• Changes in body composition (not just weight)
• Energy levels and symptoms
• Laboratory markers
• Exercise performance and recovery

Integrating Knowledge into Practice

Increasing your metabolism isn't about quick fixes or "miracle" supplements. It's about creating an environment where your body's natural metabolic processes can function optimally. The functional nutrition approach recognises that metabolism is influenced by countless factors, from the foods you eat to how you sleep to your stress levels.

Start by implementing small, sustainable changes:

1. Increase protein intake at breakfast
2. Add brief movement breaks throughout your day
3. Prioritise sleep quality
4. Stay properly hydrated
5. Incorporate strength training

Remember that consistency matters more than perfection. Your metabolism responds best to steady, supportive habits rather than extreme approaches that can't be maintained.

References

1. Lekhwani, Seema, and Narain Das Vaswani. “The Impact of Chrononutrition on Metabolic Health: Aligning Eating Patterns With Circadian Rhythms.” IP Journal of Nutrition Metabolism and Health Science, vol. 7, no. 3, Oct. 2024, pp. 105–09. https://doi.org/10.18231/j.ijnmhs.2024.019. 
2. “How to Increase Your Metabolism for Weight Loss?” Citizens Speciality Hospital, www.citizenshospitals.com/blogs/how-to-increase-your-metabolism-for-weight-loss.