Nutrition Fundamentals for Health and Weight Loss
- Nick T
- Aug 26
- 13 min read
This is a comprehensive guide, put together to give you the fundamentals of nutrition - what really matters for maintaining a healthy weight, improving exercise performance, and reducing chronic disease risk.
In a world full of nutrition fads, myths, and social media trends, this guide will help you cut through the noise.
Here’s what to expect:
A breakdown of nutrition fundamentals you can trust.
Practical strategies for weight loss and healthy eating
Myth-busting of common diet misconceptions.
Insights into popular diets and their pros / cons.
Tools for tracking, planning, and building long-term habits.
Sample meal plans and portion guides.
Nutrition doesn’t need to be extreme. The best diet is the one that creates sustainable results and fits your lifestyle.
Energy Balance - The Foundation of Weight Loss
Albert Einstein famously said, “Energy cannot be created or destroyed, only transformed.”
This principle applies to human metabolism: all foods contain energy (measured in calories), and how you manage intake vs. expenditure determines whether you lose, gain, or maintain weight.
Energy surplus (calories in > calories out) → excess stored as fat (weight gain)
Energy deficit (calories out > calories in) → body taps fat stores (weight loss).
All diets that lead to weight loss do so by creating a calorie deficit - whether low-carb, keto, vegan, or intermittent fasting.
This is great news because it means you could adopt one of these diets if it suits you, or you could not.
If you decided on a less restrictive pattern of eating - allowing for occasional slices of bread or birthday cake - as long as a calorie deficit is maintained, weight loss can occur. The strategy matters less than consistency and sustainability.
Myth Busted: There are no “fattening” or “weight loss” foods - only a diet pattern that creates a calorie surplus or deficit.
Calories & Macros
What is a Calorie?
A unit to measure energy. Just like Km measure distance
1 calorie = energy required to raise 1g of water by 1°C.
In nutrition, we measure in kilocalories (kcal), commonly just called calories.
Calorie content per gram:
Carbohydrates = 4 kcal/g
Protein = 4 kcal/g
Fat = 9 kcal/g
Alcohol = 7 kcal/g
Kilojoules: Food labels in Australia use kilojoules (kJ) instead of calories. To convert kJ to kCals, simply divide kJ by 4.18 (418kJ ≈ 100 calories).
The Thermic Effect of Food (TEF)
Different foods use different amounts of energy to digest and absorb. This effect, known as the Thermic Effect of Food (TEF), means that about 10% of your Total Daily Energy Expenditure (TDEE) is influenced by your food choices.
The different macronutrients have different thermic effects. The percentages below are those of the energy lost through digestion for each macro:
Protein = up to to 30%
Carbohydrates = up to 15%.
Fats = up to 5%.
This is why protein intake is crucial during weight loss. Not only does it help preserve muscle mass and keep you fuller for longer, but it also has the added benefit of burning more energy during digestion.
Macros Explained
Protein - The Builder
Protein is often considered the most important macronutrient for anyone interested in fat loss, muscle gain, or simply maintaining health. Unlike carbohydrates and fats, protein has multiple unique benefits beyond providing energy:
Builds and repairs muscle, hormones, enzymes, and immune cells.
Preserves muscle mass during fat loss.
Highly satiating and metabolically expensive to digest.
Daily target:
Around 1.2 – 2.0g per kg body weight is generally sufficient for most healthy adults. Aim for the higher end if in a calorie deficit and/or aiming to maximise muscle mass.
In real life: A 70kg person would aim for 85 - 140g protein per day - toward the higher end as an insurance policy. It's a safe bet to aim for 20 - 40g protein at each meal, spread across the day.
Examples of foods containing 20 - 40g protein per serve:
1 palm-sized (100–120g cooked) chicken breast = ~30g protein
1 small can tuna (95–100g) = ~22g protein
3 large eggs = ~18–20g protein (scrap as many yolks as you'd like to reduce fat/calories)
200g Greek yoghurt (low fat) = ~20g protein
1 scoop whey protein powder (30g) = ~25g protein
150g firm tofu = ~20g protein
1 cup cooked lentils = ~18g protein (pair with grains to complete amino acid profile).
1 cup cooked rice + 1 cup cooked beans together = ~20–22g protein
Carbohydrates - The Fuel
Carbohydrates are a broad food category, ranging from table sugar to bread, pasta, whole grains, fruits, and vegetables.
All carbohydrates are ultimately broken down into glucose, the brain's preferred energy source. Glucose is stored in the muscles and liver as glycogen, ready to fuel movement and activity, especially at higher intensities.
Myth Busted: Carbs don’t make you fat. Overeating calories does. Many studies have examined a wide range of carbohydrate types and amounts, and consistently found that when calories are controlled, weight change is the same.
Types of carbohydrates:
Simple carbs: sugars such as glucose, fructose, sucrose (found in fruit, honey, table sugar). May be appropriate shortly before intense exercise if a meal hasn't been eaten within a few hours.
Fruit may contain sugar, but behave differently in the body due to its' fiber content. Eat fruit.
Complex carbs: starches and fiber found in foods like bread, pasta, rice, legumes, and whole grains.
Starchy vegetables like potatoes, corn, pumpkin.
Non-starchy vegetables like broccoli, spinach, zucchini, etc. - high in fiber and micronutrients.
Food for thought: Is it the pizza dough that's the problem, or the generous serve of cheese on top? Or the whole composition of the food that makes it hyper-palatable?
Fats — The Essential Support
Fats are essential for many functions in the body. We need a certain minimum intake for hormones, brain and nerve health, and absorption of fat-soluble vitamins (A, D, E, and K).
To put this into perspective:
1 teaspoon olive oil = ~40 calories
1 regular spread of butter (5g) = ~35 calories
1 thick spread of peanut butter (17g) = ~100 calories
10 cashews = ~90 calories
Compare this to:
1 medium apple = ~80 calories
1 slice wholemeal bread = ~80 calories
2 cups steamed broccoli = ~60 calories
This shows how easy it is to consume extra calories from fats in small portions, compared to much larger (and more filling) portions of fruits or vegetables.
Types of fats and their impact:
Saturated fats: Best limited to <10% of daily energy intake. High intakes are associated with increased LDL ( "bad" ) cholesterol and cardiovascular risk. Found in fatty cuts of meat, butter, coconut oil, cream, pastries, and many processed foods.
Unsaturated fats: Generally health-promoting or neutral. Include monounsaturated fats (e.g., olive oil, avocados, nuts) and polyunsaturated fats (e.g., fatty fish, flax, walnuts). Replacing saturated fats with unsaturated fats consistently shows improvements in blood cholesterol and reduced risk of heart disease.
Trans fats: Artificially produced (partially hydrogenated oils). These should be avoided entirely, as they increase heart disease risk. They are mostly removed from the food supply.
Seed oils (such as canola, sunflower, or soybean oil) are often claimed to be “toxic” or “inflammatory.” High-quality research does not support this. In fact, these oils are rich in polyunsaturated fats, which can lower LDL cholesterol and reduce cardiovascular risk when they replace saturated fat in the diet.
Micronutrients & Fiber
Micronutrients
Micronutrients (vitamins, minerals, phytochemicals) don’t provide energy but are essential for nearly every physiological process. They support energy production pathways, muscle recovery / building processes. For example:
B‑vitamins act as cofactors in energy metabolism
magnesium supports muscle contraction and relaxation, and
zinc plays a role in tissue repair.
Common deficiencies can have big impacts on health and performance:
Calcium: important for bone health and muscle contraction. Low intake increases risk of osteoporosis and stress fractures.
Vitamin D: crucial for calcium absorption, immune health, and muscle function. Deficiency is linked with low bone density, fatigue, and higher injury risk.
Iron: needed for oxygen transport in red blood cells. Deficiency leads to anaemia, fatigue, reduced endurance, and impaired recovery.
Key takeaway: A balanced diet built on mostly whole, minimally processed foods is the best way to cover your nutrient needs. If you follow a specific diet or have health concerns, get your levels checked with your doctor and seek professional nutrition support when needed.
Fiber
Fiber is broadly beneficial for health. It supports digestion, gut health, cholesterol regulation, and overall disease prevention.
Because there are many different types of fiber, a varied diet rich in plant foods is recommended.
Soluble fiber: slows digestion, forms gels, and feeds gut bacteria.
Common sources include oats, barley, legumes (beans, lentils, chickpeas), apples, citrus fruits, pears, carrots, and psyllium husk.
Certain soluble fibers such as those in oats, citrus and legumes can lower LDL ("bad") cholesterol.
Insoluble fiber: adds bulk, aids digestion, and helps maintain regular bowel movements (e.g., whole grains, vegetables).
Key Findings: Large population studies consistently show that higher fiber intakes are linked to lower risk of heart disease, type 2 diabetes, and all-cause mortality. Eating more than 30g of fibre per day, compared to low intakes, is linked to a 15-30% lower risk of dying early.
Daily Fiber targets: 30g (men), 25g (women).
Popular Diets — The Pros & Cons
We’ve all heard friends, family, and social media personalities promoting certain diet fads as the one true path to weight loss and/or health.
The truth is, when it comes to body weight, the key driver is still energy balance - calories in versus calories out. And it's the main reason why most diets work.
Key Point: The “best” diet is the one you can stick to long-term. Adjust your diet as LITTLE as possible so as to deviate from your habits as LITTLE as possible.
Popular diets are often restrictive of a food or food group, thus driving a calorie deficit. Cut out carbs & you cut out sugary cereal, chips, pizza, doughnuts, the weekly office birthday cake. You cut out calories.
That said, weight is not the only reason to consider a diet. Beyond calories, some diets ensure adequate nutrient intake, while others may make this harder.
For example:
Intermittent fasting: May help reduce calorie intake by reducing the eating window. Depending on the eating window (16:8, Alternate day, 5:2 diet) it can be challenging to meet protein or micronutrient needs. There is evidence to shown that infrequent or consistently low protein intake can negatively affect muscle maintenance, body composition, and recovery.
Keto: Can control appetite, but often falls short on fibre targets and may promote higher saturated fat intake instead of healthier unsaturated fats. It may also lead to high processed meat intake, shown to increase cancer risk, particularly colorectal cancer.
Rapid weight loss is often seen in 1-2 weeks of a low carb / keto diet, because carbs hold water. Eliminating carbs sheds water weight, giving impressive initial numbers on the scales.
Plant-based diets: Offers plenty of fiber and micronutrients, but nutrients of concern include essential amino acids (protein), vitamin B12, iron, and calcium. It could be a perfectly healthy diet, but often requires planing and learning to ensure nutrient targets are met.
Practical Tools for Success
Planning for Weight Loss
Below are helpful tools strategies and help you to create sustainable habits that match your lifestyle, rather than short-term fixes.
Calorie awareness: Understand that energy balance drives weight change. Tracking can help, but even simple portion awareness is powerful.
Realistic and reasonable timeframe: Try not to lose the weight too fast. 0.5 - 1kg per week is sustainable and will influence less muscle loss. Higher starting body fat may allow for loss on the higher end (1kg/week). If already lean, aiming to get leaner, go slow.
Think of the diet after the diet: Ideally it's not a "diet", but a long term dietary pattern. If doing a short term program, plan for the weeks after so as not to return to bad habits.
Protein first: Prioritise 20–40g protein each meal to support muscle, and increase fullness.
Fill the plate with plants: Aim for half the plate from vegetables and salad to hit nutrient targets and increase fullness.
Carb and fat flexibility: Adjust based on preference and activity levels.
Remember that fats are calorie dense.
Carbs fuel intense/long duration training. Lean into carbs on training days or nights before morning exercise.
Mindful eating: Slow down, avoid distractions, and tune in to hunger/fullness cues.
Healthy is not always helpful for weight control.
Mind portions of nuts, avocado, peanut butter, cooking oils.
Don't forget milk based coffees can add up.
Limit “more-ish” foods at home: Weight gain is often driven by foods that are easy to over-consume (ice cream, chips, chocolate). Keeping these out of the home removes the temptation all together.
Use the “apple test”: Before grabbing chocolate or biscuits, pause and ask yourself, “Am I hungry enough to eat an apple?” If the answer is no, it may be a craving rather than true hunger.
Enjoy your favourite foods in moderation: Total restriction often backfires. Food should be enjoyed, and a sustainable weight loss journey should not totally suck!. Allowing room for favourite treats in a mindful way supports adherence.
Tips for eating out
Choose grilled over fried.
Add vegetables/salads wherever possible.
Be mindful of sauces and dressings - get them on the side.
Share "treat" foods with others (chips, desserts)
Remember alcohol calories add up but don't fill you up
Modify your diet earlier in the day or week to cater for occasional indulgant meals/days
Tips for eating on the road
Taking some healthier food and water with you if you're on the road.
Plan your day where you could stop at a bakery or café for lunch and ask for a salad,
wholegrain roll or wrap.
Avoid pies, pastries and other processed foods.
Travel with a protein shake or bar.
Tips for social settings
Offer to take a salad or fruit platter to dinner or lunch with friends.
Try to serve yourself, so that you can control your portion size.
Plan some social activities that don't involve food or alcohol
Relax and enjoy good food with good people. One meal doesn't ruin progress
Portion Sizes & Tracking Calories
A balanced approach to nutrition means understanding what counts as a rough serve from each food group, and how those serves add up to support energy balance and nutrient needs.
Below are examples adapted from the Australian Dietary Guidelines and a more crude, but useful measure by using your hand.
Portion Control by Hand
Using Food Tracking Apps
You could absolutely track your food intake for a few days - weeks to understand your eating habits, quantities, and what is contained within the foods you regularly eat.
Use apps like Easy Diet Diary (iOS) or MyFitnessPal
Focus on achieving targets of total calories and protein. Carbs and fats can be tracked and enjoyed by preference or activity level.
Do not add your exercise calories into the diet tracking App. They will add calories onto your daily target if exercise energy has been expended. However, exercise trackers can be quite (very) inaccurate.
If tracking becomes stressful, or you are inclined to become fixated by it, it may be best reserved for short periods to learn, and review your intake.
If you plan to track food for weight loss, how do you calculate your calories needs? I strongly suggest reading this article
Exercise
Resistance Training
Lifting weights is one of the most valuable - and often overlooked - tools for health and sustainable weight loss.
Many people turn straight to cardio when thinking about burning calories, but strength work offers unique benefits that cardio alone cannot provide.
Lifting weights - whether bodyweight, home exercise or a gym routine, offers the following benefits:
Preserves muscle mass: Essential when in a calorie deficit so weight loss comes from fat, not valuable muscle. This is especially important in later decades, as muscle mass declines with age. Muscle preservation strongly links to longevity.
Maintains a "toned" appearance: Due to the development or maintenance of muscle mass, and body fat loss.
Raises metabolism: More muscle means more calories burned at rest. In reality, it's not an enormous increase, but it's certainly a bonus.
Supports bone and joint health: Improves bone density, posture, and injury prevention.
A different perspective: Try to avoid the view of exercise purely as a calorie burner. The “I earned this food” or "I'd better burn it off" mentality may lead to an over reliance on cardio, over training, and viewing exercise as a punishment, rather than empowerment.
Action Step Aim for:
2–3 resistance training sessions per week, hitting major muscle groups.
6-8 sets of work per major muscle group, split up over the week.
Prioritise exercises that provide additional functional benefit for your needs (squats, pushing, pulling, step ups).
Cardio that you enjoy - either moderate intensity for 20+ mins or more intense forms for shorter durations.
Exercise Guidelines recommend a minimum of 150min of moderate, or 75min of vigorous cardio exercise per week for general health.
This is a daunting amount for many, hence why few achieve it.
Do what you can, understanding that these recommendations are based on strong evidence of reduced disease risk, whereby more exercise impacts further risk reduction.
As weight loss occurs, non-exercise movement can subconsciously become reduced, contributing to plateaus.
monitor daily steps as a proxy for general daily activities and increase where needed
Tracking Progress Beyond the Scale
The weight on the scale is one measure of how body shape is changing. Over time, we would want to see this trend downward if fat loss is the goal.
However, the trend is not linear — it’s completely normal to see fluctuations of around 1kg from day to day.
This can be caused by several factors, such as:
Water retention from exercise
Higher carbohydrate intake (3g water to each gram of carbs)
Higher salt intake
Creatine supplement use (water retained in muscle)
Bowel movements (or not)
Daily fluctuations aside, when resistance training is added, increased muscle mass may contribute to what looks like a slower rate of weight loss. This is positive that muscle is being preserved or gained while losing body fat.
Other objective measures:
Circumference measurements: Waist, hip, thighs, and any other areas you care to monitor.
Progress photos: Taken in consistent lighting, at the same time of day (ideally after a toilet run), can provide a clear picture of body shape changes over time.
Clothing fit and comfort: Looser pants or dresses and tighter belts are meaningful indicators.
Subjective and Performance measures:
Feeling stronger, fitter and more resilient is a testament to your hard work, and a reminder of the primary reason to exercise.
If you’re lifting heavier, performing more reps, you’re likely developing more muscle. If you're not, consider if you're fuelling training enough.
You could try setting specific performance goals for enjoyment and self-empowerment.
Running 5km in a target time
Join a fitness event
Lift a certain weight for a certain exercise
Perform your first pull-up or pushup
Other Successes: Focusing on strength, fitness, function and mood provides more ways to celebrate progress and makes the journey more enjoyable.
TLDR - Summary in 10 points
Nutrition doesn’t need to be complicated. The fundamentals remain the same:
Consistency is ABSOLUTELY key. It's not a catch phrase
Create a calorie deficit for weight loss.
Avoid a calorie deficit to maintain weight, eat additional calories to gain muscle (with weight training).
Prioritise protein and whole foods. Balance carbs and fats based on preference and activity.
Carbs won't make you fat. Over eating them will.
Adjust your expectations - temper your enthusiasm. More than 1kg weight loss per week has downsides.
Use unsaturated fats over saturated fats for better heart health.
Embrace flexibility - No single food makes or breaks your diet.
The further you deviate from usual habits, the harder it’ll be to sustain.
No single food is “good” or “bad”. But rather, “healthy” or “not so healthy”
Eat mostly healthy foods, most of the time
Exercise because it’s bloody good for you. Not solely for weight loss or punishment.
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