Your Body Programme · Fat Loss

The Lean Body Type

Naturally slim with a fast metabolism. Finds muscle hard to build and keep. Handles carbohydrate very well.

Previously called Ectomorph
Fast metabolism
Handles carbs very well

How to use this page. Start with your plan at a glance. Sections 02 to 06 explain how your body type works and what your plan asks you to do, with the reason behind each step. If you just want the essentials, that is all you need to read. Section 07 is for the curious minded: what is happening inside your body and why your plan is built the way it is.

Your plan also includes three other parts referred to on this page: your nutrient breakdown table (your personal daily targets), your food list, and the nutritional data table (fruit and vegetable sections).

01 · Your plan at a glance

Your plan on one page

Your exact daily amounts are on your nutrient breakdown table. These are the rules they are built on.

Calorie target

5 to 10% below maintenance

Small deficit only

Daily protein

1.8 to 2.0g per kg

of body weight

Target fat loss

0.3 to 0.5% a week

of body weight

Eating window

12 hours

For example 7am to 7pm

Meals a day

4 to 5

Every 2 to 2.5 hours

Pre-training meal

1 to 2 hours before

Early-morning training

Light snack

30 to 45 min before, no fat

During training

Water

Add a carbohydrate drink if the session lasts over 45 min

Post-workout shake

Within 10 to 20 min

Carbohydrate timing

Every meal

Spread through the day

Last meal

1.5 to 2.5 hours before bed

At least

Rest days

Carbs down 10%

Day 1. Down 20% on day 2 in a row.

02 · Your body type and fat loss

Fat comes off easily. Muscle is the priority.

You are a Lean body type on a fat loss programme. Losing fat should be relatively easy for you, because your body type burns energy quickly and releases stored fat readily. Your main priority is to protect the muscle you are building in the gym.

Your body type finds it hard to build and hold on to muscle, so it is essential not to cut calories or carbohydrates too far. Your muscle fibres are mostly the endurance type, which grow less, and your fast metabolism uses energy quickly. Cutting too hard causes your body to break down muscle for energy, and losing muscle slows your metabolism. A slower metabolism makes fat loss harder. One of our main goals, therefore, is to burn fat by building muscle, which in turn speeds up your metabolism.

In simple termsMetabolism: the total amount of energy (calories) your body uses each day to stay alive, move and recover. Muscle is "expensive" tissue to run, so the more muscle you carry, the more calories you burn, even at rest.

Your calorie target is set only 5 to 10% below your maintenance calories (the amount that would keep your weight the same). A small deficit is essential for your body type. Cutting deeper puts your muscle at serious risk.

Cutting calories below our recommended amount does more than break down muscle. Your body reads a large shortage as a threat. This is a built-in survival mechanism: in times of famine, stored fat is what keeps us alive, so your body works to protect it and takes protein from your muscles to turn into energy instead, which is exactly what we are trying to avoid. When your stored carbohydrate runs low, your body can break down muscle protein and turn it into sugar for fuel. This is also why the leaner you become, the harder it is to lose fat: as your fat stores shrink, your body sends out stronger hunger signals and slows your metabolism to protect what is left.

What to do, and why

Protect your muscle. It is the engine that keeps your metabolism high.
Never cut calories or carbohydrates below the targets in your plan.
Why: a deeper cut switches the fuel gauge AMPK on more strongly, which brakes muscle building and makes your body break muscle down for fuel.
Eating too little makes your body break down muscle and protect its fat stores.
Why: your body reads a large shortage as famine, so it guards its fat and uses muscle protein for energy instead.
Aim for slow, steady fat loss of around 0.3 to 0.5% of your body weight per week.
Why: for your body type, faster loss usually means muscle loss.
Keep up your gym training. It tells your body the muscle is needed and should be kept.
Why: lifting switches on mTORC1, the muscle-building switch, which protects muscle even in a calorie deficit.
Have your targets reviewed every 2 to 4 weeks and adjusted as you go.
Why: the amount of food you need changes as you lose fat.

03 · Metabolism, blood sugar and carbohydrates

Keep your fuel topped up

As a Lean body type you have a naturally fast metabolism, so you burn through your stored fuel more quickly than the other body types. Keeping your fuel stores topped up throughout the day is important, as it limits muscle breakdown during training. Eating little and often keeps your blood sugar steady, keeps insulin stable, and protects your muscle.

In simple termsInsulin: a hormone released by the pancreas when you eat, mainly in response to carbohydrate. Its job is to move sugar out of your blood and into your muscles and liver for storage. While insulin is high, fat burning slows right down, because your body is busy storing fuel rather than releasing it.

You are carbohydrate tolerant, which means you can eat carbohydrates without the fat gain other body types experience. This is because your muscles are very sensitive to insulin: they take sugar out of the blood quickly and store it as glycogen, rather than leaving it to be stored as fat. This does not mean eating as many carbohydrates as possible. The right carbohydrates at the right time will protect your muscle.

In simple termsGlycogen: the form in which carbohydrate is stored in your muscles and liver. Think of it as your body's ready-to-use fuel tank.

What to do, and why

Your fast metabolism uses fuel quickly, so keep your stores topped up.
Why: if your stores run low, your body turns to muscle protein for fuel.
Eat little and often to keep blood sugar and insulin steady.
Why: small meals cause small, gentle rises in insulin rather than big spikes and dips.
You handle carbohydrates well, but the type and timing still matter.
Why: your muscles respond strongly to insulin and have plenty of GLUT4 "doors" to let sugar in.
Carbohydrates protect your muscle, so don't cut them out.
Why: when glycogen runs low, your body breaks down muscle protein to make sugar instead.

Watch for: feeling shaky, light-headed or very hungry between meals. It is a sign your blood sugar has dropped too low and you need to eat more regularly.

04 · Meal timing and frequency

Little and often

Your body type has a smaller digestive capacity and smaller fuel stores than the other body types, and you tend to feel full quickly. Less muscle mass means less room to store glycogen, and your stomach empties quickly, so fuel from each meal is used up fast. Be careful not to overeat at any one sitting: fuel your body cannot store is more likely to be stored as fat. Smaller, more frequent meals spread across the day suit you best.

Spreading meals evenly also helps your muscles. Around 0.4g of protein per kg of body weight at each meal (about 28g for a 70kg person) is enough to switch muscle building fully on. Regular meals containing protein keep muscle repair "switched on" throughout the day.

What to do, and why

Eat breakfast within an hour of waking, whether or not you are training.
Why: after the overnight fast your liver glycogen is low and your body begins breaking down muscle protein for fuel. Breakfast stops this and switches muscle building back on.
Eat 4 to 5 meals a day within a 12-hour window (for example 7am to 7pm), not counting your post-workout shake. This means eating roughly every 2 to 2.5 hours.
Why: your window is matched to your body type. The less easily a body handles carbohydrate, the shorter the window and the longer the overnight fast, when insulin is low and stored fat is burned.
Spread carbohydrate and protein evenly across your meals.
Why: this keeps your blood sugar steady and gives your muscles a regular supply of fuel and building material.
Make sure you eat after a long fast (breakfast) and after being very active (work, walking or training).
Why: these are the times your fuel stores are lowest and your muscles are most ready to absorb nutrients.
Include a small amount of low GL carbohydrate with your evening meal, as shown on your nutrient breakdown table.
Why: this tops up your glycogen for the next day and helps protect your muscle overnight.
Finish your last meal at least 1.5 to 2.5 hours before you go to sleep.
Why: this gives your body time to digest and lets insulin fall before bed, so growth hormone, released mainly in deep sleep, can do its repair work.
If your appetite is small, don't skip meals. A smoothie made with milk, oats and fruit is an easy way to get calories in without feeling over-full.

05 · Training-day nutrition

The three phases

The Energy Phase

Before and during training

Fuelling your body before and during your session. Your muscles burn mainly glycogen during hard training, so starting with full stores lets you train harder for longer.

The Anabolic Phase

The hour after training

The best time to refill your energy stores, which is why we use a post-workout shake. Straight after training your muscles soak up fuel faster than at any other time. Because your body type finds it hard to hold on to muscle, getting the right nutrients in promptly helps you make the most of the work you have put in. Have your shake within 10 to 20 minutes of finishing. Your window is the shortest of all the body types because your small glycogen stores empty fastest and your body turns to muscle for fuel soonest.

Growth, Repair and Recovery

The 24 hours after training

When your body repairs, refills its fuel stores and adapts to your training. The carbohydrates you eat in this phase, including breakfast, should be low GL. This keeps your glycogen topped up and prevents muscle breakdown.

In simple termsAnabolic means "building up". After training, your body switches from using fuel to rebuilding and repairing muscle.

In simple termsGlycaemic load (GL): how much a portion of food raises your blood sugar, taking into account both how quickly its carbohydrate is absorbed and how much carbohydrate the portion contains. Low GL foods (oats, lentils, beans, sweet potato, most vegetables) release energy slowly. High GL foods (white bread, white rice, sweets, dextrose) release it quickly.

What to do, and why

Eat a meal 1 to 2 hours before training, ideally containing low GL carbohydrate, protein and fat.
Why: this gives your body time to digest, so the meal tops up your glycogen and supplies amino acids during training without sitting heavily in your stomach.
Drink about 5 to 7ml of water per kg of body weight in the 2 to 4 hours before training (roughly 350 to 500ml for a 70kg person).
Why: starting well hydrated keeps your blood volume up, so more oxygen and fuel reach your muscles. Losing just 2% of your body weight in sweat reduces performance.
Your personalised water recommendation is on your 9 Pillars Lifestyle page.
If you train early in the morning, have a light snack 30 to 45 minutes before, containing low GL carbohydrate and protein but no fat.
Why: fat slows digestion, so leaving it out means the snack is ready to use as fuel by the time you train.
Avoid training on an empty stomach. For your body type, fasted training increases muscle breakdown.
Why: with small glycogen stores, your body quickly turns to muscle protein for fuel.
If a session lasts longer than 45 minutes, sip a carbohydrate drink or eat a banana during training to protect your muscle.
Why: after about this long, your small glycogen stores start running low and your body turns to muscle protein for fuel.
Avoid fat for 90 minutes before and after training.
Why: fat slows down how quickly your stomach empties, so it would delay the fuel you need for training and the carbohydrate and protein your muscles need straight afterwards.
After training, have a post-workout shake within 10 to 20 minutes of finishing (available from any health food shop). Amounts are in the table below.
The carbohydrate after training should be high GL. We recommend dextrose (pure glucose, the simplest form of sugar, which is absorbed very quickly). See your nutrient breakdown table for the amount. If you are not having the dextrose shake, eat a high GL food from your food list instead.
Why: fast sugar raises insulin quickly, which speeds up glycogen refilling and switches off muscle breakdown.
Take 1000mg of vitamin C after training.
Why: vitamin C is needed to make collagen, the main protein in tendons and connective tissue, and supports your immune system during hard training.
Eat a meal 30 minutes to 1 hour after your shake.
Why: the shake starts recovery; a full meal keeps amino acids and glucose coming while muscle building and glycogen refilling are still running at their fastest.

Any protein or carbohydrate drinks recommended in your plan are already included in your daily calorie target.
Post-workout shake	Women	Men
Carbohydrate per kg of body weight	0.4g	0.6g
Protein per kg of body weight	0.35g	0.45g
Example	60kg woman: about 24g carbohydrate, 21g protein	80kg man: about 48g carbohydrate, 36g protein

An example training day

How the guidelines fit together on a day with afternoon training. Move the times to suit your own day: the spacing between meals and training is what matters. Lean body types spread carbohydrate across the whole day, so every meal contains some.

6:30amWater: 200 to 300ml on wakingNo carbs
7:00amMeal 1, breakfast: protein, healthy fat and carbohydrateLow GL
9:30amMeal 2: protein, healthy fat and carbohydrateLow GL
12:00pmMeal 3, pre-training: protein, fat and carbohydrateLow GL
1:30 to 2:30pmTraining: water onlyNo carbs
2:45pmPost-workout shake (within 10 to 20 min) and 1000mg vitamin CHigh GL, fast
3:30pmMeal 4: protein and carbohydrate, no fat yet (within 90 min of training)Low GL
6:00pmMeal 5, evening: protein, healthy fat and a small portion of carbohydrateSmall, low GL
10:30pmBed

06 · Food choices, rest days and daily habits

The everyday foundations

Nutrition

Your daily food choices and habits support everything above. Choose low GL carbohydrates, lean protein and healthy fats from your food list, eat plenty of varied vegetables, and adjust your carbohydrates on rest days. Any protein or carbohydrate drinks recommended in your plan are already included in your daily calorie target.

Small daily habits, such as drinking enough water, sleeping well and keeping alcohol low, make a big difference. Poor sleep, for example, raises ghrelin (the hormone that makes you feel hungry) and lowers leptin (the hormone that tells your brain you are full), making your plan much harder to stick to. Your personalised water and sleep recommendations are on your 9 Pillars Lifestyle page.

What to do, and why

Track your intake with MyFitnessPal, a free food-diary app that adds up your calories and macronutrients (protein, carbohydrate and fat) for you.
Why: most people underestimate how much they eat. Tracking shows exactly how close you are to your targets.
Drink 200 to 300ml of water as soon as you wake.
Why: you lose water overnight through breathing and sweating, so you wake slightly dehydrated, and even mild dehydration reduces energy and concentration.
Your personalised water recommendation is on your 9 Pillars Lifestyle page.
Keep drinking regularly through the day: roughly 30 to 35ml per kg of body weight (about 2 to 2.5 litres for a 70kg person), plus extra on training days.
Why: water carries nutrients into your cells and waste out, and muscle is about three-quarters water.
Your personalised water recommendation is on your 9 Pillars Lifestyle page.
If you sweat heavily, weigh yourself before and after training. For every 1kg lost, drink about 1.25 to 1.5 litres of fluid over the next 2 to 4 hours, with a little salt or an electrolyte drink.
Why: you keep losing fluid through urine after training, so you need to drink more than you lost, and the salt helps your body hold on to it.
Your personalised water recommendation is on your 9 Pillars Lifestyle page.
Eat low GL carbohydrates at all times except straight after training.
Why: low GL carbohydrate releases sugar slowly, so insulin rises gently and fat release is not switched off for long. Straight after training your muscles want sugar fast, so high GL is better then.
Choose lean meats from your food list and spread your protein evenly through the day.
Why: each meal triggers a separate burst of muscle building, so spreading protein out gives you more building periods across the day.
Include protein at every meal. As a rough guide, a palm-sized portion of meat, fish, eggs, Greek yoghurt or tofu. Your exact amounts are on your nutrient breakdown table.
Why: each protein-rich meal switches muscle building on again.
Choose healthy fats from your food list and spread them through the day.
Why: healthy fats such as olive oil, nuts, oily fish and avocado are needed to make hormones, including testosterone, and to absorb vitamins A, D, E and K.
Nutrients to focus on: B vitamins (wholegrains, eggs, meat), which help turn food into energy; magnesium and zinc (leafy greens, nuts, seeds), which support muscle function and repair; and calcium and vitamin D (dairy or fortified alternatives, oily fish) for strong bones.
Why: Lean body types tend to have lighter bones.
Limit fruit to 2 to 3 pieces a day because of its sugar content. Most of your weekly fruit should come from section A of the nutritional data table.
Why: fruit sugar (fructose) is handled mainly by the liver, which can turn excess into fat once its own glycogen stores are full.
Eat 6 to 12 portions of vegetables a day, mostly from section A of the nutritional data table.
Why: this provides the fibre you need. Fibre keeps you full for longer and slows the release of sugar into the blood.
Vary the type and colour of your fruit and vegetables.
Why: different colours supply different vitamins, minerals and protective plant compounds.
On a non-training day, reduce your carbohydrates by 10%. On a second non-training day in a row, reduce them by 20%.
Why: without training your muscles use less glycogen, so they need less refilling, and even less on a second rest day.
Aim for 7 to 9 hours of sleep a night.
Why: most growth hormone is released in deep sleep, when your muscles repair and your nervous system recovers. Poor sleep also raises cortisol, the stress hormone that encourages muscle breakdown and fat storage.
Your personalised sleep recommendation is on your 9 Pillars Lifestyle page.
Keep alcohol to a minimum.
Why: your body burns alcohol before anything else, which pauses fat burning, and it can interfere with muscle repair.
These are guidelines, not strict rules. Some may be hard to stick to. Just do the best you can.

07 · For the curious minded

The science behind your plan

For those who want to know more: what is happening inside your body and why your plan is built the way it is. Tap any heading to open it.

The science of fat loss

Your body stores energy in two main places: as fat in your fat cells, and as glycogen (stored carbohydrate) in your muscles and liver. To lose fat, your body must take in less energy than it uses, an energy deficit, so that it has to make up the difference by releasing stored fat.

When energy is short, a fuel gauge inside your cells called AMPK switches on. It tells your body to release fat from your fat cells, a process called lipolysis, and burn it in your mitochondria. Low insulin, together with the hormones adrenaline and noradrenaline (released during exercise), opens the fat cells' doors. This is why keeping insulin low between meals matters so much for fat loss.

In simple termsAMPK (AMP-activated protein kinase): a fuel gauge inside every cell. When energy runs low, during exercise or when you eat less than you use, AMPK switches on. It tells the cell to burn fat and sugar for energy and to pause energy-hungry jobs such as building new muscle.

In simple termsLipolysis: the release of stored fat from your fat cells. The fat is split into fatty acids, which travel in the blood to your muscles and other tissues to be burned for energy. Insulin slows lipolysis down; adrenaline, noradrenaline and low insulin speed it up.

In simple termsMitochondria: tiny "power stations" inside your cells where fat and carbohydrate are burned with oxygen to make energy. More mitochondria means more capacity to burn fat.

The challenge is that AMPK also slows muscle building, and your body treats a large energy shortage as a threat: it lowers leptin (the hormone that tells your brain you have enough fat stored), slows your metabolism and starts breaking down muscle for fuel. Your plan therefore creates a deficit large enough to release fat but small enough to protect muscle, with enough protein and regular training to keep the muscle-building switch, mTORC1, turned on.

In simple termsmTORC1: the master "build" switch inside your muscle cells. It is switched on by lifting weights, by protein (especially the amino acid leucine) and by insulin, and switched off when energy is short. When it is on, your muscles make new protein.

The key facts

Main pathways

AMPK (the fuel gauge) and lipolysis: releasing and burning stored fat

Main fuel

Stored body fat at rest and during easy activity; glycogen during hard training

What your nutrition must do

Create a controlled deficit, keep insulin low between meals, keep protein high and fuel training so muscle is kept

Why your body type changes the plan

These pathways are the same in every body. What your genetics change is how strongly each one works: your mix of muscle fibres, how sensitive your muscles are to insulin, how fast your metabolism runs and how much fuel you can store. That is why each body type has its own fat loss plan.

In simple termsMuscle fibre types: muscles are made of different fibres. Slow-twitch (Type I) fibres are built for endurance: efficient and slow to tire, but they do not grow much. Fast-twitch fibres (Type IIa, and the most powerful, Type IIx) produce more force and grow more easily, but tire quickly. Your genetics largely set your mix, and it differs between body types.

In simple termsInsulin sensitivity: how well your muscles respond to insulin. High sensitivity means a small amount of insulin moves sugar quickly into your muscles. Low sensitivity (insulin resistance) means more insulin is needed, fat burning stays switched off for longer, and spare sugar is more easily stored as fat. It is partly genetic but improves greatly with training.

Body type	Genetic tendencies	So the plan…
Lean (you)	Mostly slow-twitch fibres; very high insulin sensitivity; fast metabolism; small glycogen stores	Small deficit; carbohydrate every meal; 4 to 5 meals
Lean Athletic	Mixed fibres leaning slow-twitch; high insulin sensitivity; fast metabolism	Moderate deficit; carbohydrate every meal; 4 meals
Athletic	Balanced fibres; good insulin sensitivity; efficient fat release and glycogen storage	Larger deficit tolerated; carbohydrate evenly spread; 3 to 4 meals
Athletic Power	Fast-twitch leaning; lower insulin sensitivity; fewer mitochondria; slower fat release	Larger deficit; 3 meals; carbohydrate only after activity
Power	Mostly fast-twitch; lowest insulin sensitivity; fat release easily blocked by insulin; large muscle mass	Largest deficit with diet breaks; 2 to 3 meals; carbohydrate only after activity

How fat loss works in your body, step by step

The energy gapYou eat a little less energy than your body uses each day. Your body still needs that energy, so it has to find the difference from its own stores.
The signal to release fatBetween meals your insulin falls, and AMPK switches on because energy is short. During exercise your body also releases adrenaline and noradrenaline. Together, low insulin and these hormones tell your fat cells to open up.
Fat leaves the fat cellInside each fat cell, fat is stored as triglycerides: three fatty acids joined together. The enzyme hormone-sensitive lipase cuts them apart, and the fatty acids pass into your blood to be carried to your muscles.
Fat is burnedIn the muscle, the fatty acids are carried into the mitochondria by a transporter called carnitine, and broken down step by step to make ATP, the energy that powers every cell. The leftovers are carbon dioxide and water: about 80% of the fat you lose leaves your body in your breath.
The fat cell shrinksFat cells do not disappear when you lose fat. They empty and shrink, which is why your shape changes.
Muscle is protectedBecause AMPK also brakes muscle building, a deficit can eat into muscle. Your gym training and enough protein keep mTORC1 turned on, so the energy gap is filled from fat rather than muscle.

In simple termsHormone-sensitive lipase: the enzyme inside fat cells that cuts stored fat into fatty acids so they can be released and burned. Adrenaline switches it on; insulin switches it off.

In simple termsATP (adenosine triphosphate): the energy currency of every cell. All the fuel you eat, carbohydrate, fat and protein, is turned into ATP, and ATP is what directly powers every muscle contraction.

How these steps work in your body type: in a Lean body, steps 3 and 4 run quickly: hormone-sensitive lipase is very active and your slow-twitch muscles are packed with mitochondria. Step 6 is your weak point. Your muscle is easily used for fuel, so protecting it comes first.

Why your plan suits your body type

Lean body types tend to have more slow-twitch muscle fibres: endurance fibres that use fuel efficiently but do not grow as easily as fast-twitch (power) fibres. This is one reason muscle is harder for you to build and keep.

Your genetics give you mostly slow-twitch fibres, muscles with high insulin sensitivity that clear sugar from the blood quickly, a fast metabolism and a lot of everyday movement. You release and burn fat easily, but your small glycogen stores run down fast and your body turns to muscle for fuel when energy is short. That is why your plan uses only a small deficit, includes carbohydrate at every meal and spreads food across 4 to 5 meals.

Your metabolism and carbohydrate handling

Your fast metabolism comes from several inherited traits: a busy sympathetic nervous system (the body's "accelerator", which raises heart rate and energy use), higher thyroid hormone activity, and a high level of everyday movement, known as NEAT. Your muscles also carry plenty of GLUT4 "doors" that let sugar in and plenty of mitochondria to burn it, so carbohydrate is cleared from your blood quickly and used or stored as glycogen rather than turned into fat. The downside is that your stores are small and empty quickly, which is why regular meals matter.

In simple termsNEAT (non-exercise activity thermogenesis): the calories you burn through everyday movement that is not planned exercise: walking, standing, fidgeting, household jobs. It can differ by hundreds of calories a day between people.

In simple termsGLUT4: a "door" (transporter) that lets sugar from the blood into your muscle cells. Insulin moves GLUT4 doors to the surface of the cell; exercise does the same thing on its own, without needing insulin. The more GLUT4 doors your muscles have, the better you handle carbohydrate.

Why your meal timing works

Your stomach empties quickly and your muscles hold relatively little glycogen, so the fuel from each meal is used up fast. Each meal containing enough protein also switches muscle building on for a few hours before it needs triggering again. Eating every 2 to 2.5 hours keeps both your energy supply and your muscle building steady.

In simple termsLeucine threshold: leucine is one of the amino acids, the building blocks of protein. It acts as the trigger that switches muscle building fully on. A meal needs about 2 to 3g of leucine to reach this threshold, roughly the amount in 25 to 40g of protein from meat, fish, eggs or dairy.

What happens around training

In the first 30 to 60 minutes after training, glycogen synthase, the enzyme that refills your muscle fuel stores, is at its most active, and exercise has moved GLUT4 doors to the surface of your muscle cells so sugar can flood in. With small stores that empty quickly, this is your fastest way to refill and stop your body breaking muscle down for fuel. Fast carbohydrate plus protein also raises insulin, which switches muscle breakdown off and, together with leucine, switches mTORC1 on. Your muscle-building response after training is modest but long-lasting, up to 48 to 72 hours, so regular meals in Phase 3 matter as much as the shake.

In simple termsGlycogen synthase: the enzyme that builds glycogen. It links sugar molecules together into chains for storage in your muscles, and is most active in the first 30 to 60 minutes after training, when your stores are low.

Food, sleep and your body

Low GL foods and fibre slow the speed at which sugar reaches your blood, so insulin rises gently instead of spiking. Fibre also feeds the healthy bacteria in your gut, which make compounds that improve insulin sensitivity and appetite control.

Sleep matters because even one poor night can reduce insulin sensitivity the next day and raise cortisol, the stress hormone that encourages muscle breakdown and fat storage around the middle. Your fast energy turnover also uses up B vitamins, magnesium and zinc more quickly.

Electrolytes: what they do and why they matter

Electrolytes are minerals that carry a tiny electrical charge when they dissolve in your body's fluids. That charge is what lets your nerves send signals and your muscles contract: every heartbeat and every rep depends on them. Electrolytes also decide where water goes in your body: sodium holds water outside your cells and potassium holds it inside, so the balance between them controls how well hydrated your muscles and blood stay.

In simple termsElectrolytes: minerals such as sodium, potassium, magnesium, calcium and chloride that carry an electrical charge in your body fluids. They power nerve signals and muscle contractions and control the balance of water inside and outside your cells.

When you sweat you lose mostly water and sodium, roughly 0.5 to 1.8g of sodium in every litre of sweat, with only small amounts of potassium, magnesium and calcium. Running low can show up as cramp, headaches, tiredness, dizziness and weaker training. A balanced diet covers most people's needs; a pinch of salt or an electrolyte drink matters mainly after long or very sweaty sessions, or in hot weather.

Electrolyte	What it does	Good food sources
Sodium	Holds water in your blood and around your cells; carries nerve signals. The main electrolyte lost in sweat.	Salt, stock, olives, cheese, bread
Potassium	Holds water inside your cells; controls heart rhythm and muscle contraction.	Potatoes, bananas, beans, lentils, leafy greens, avocado
Magnesium	Needed by over 300 enzymes, including those that make energy (ATP); helps muscles relax and supports sleep.	Leafy greens, nuts, seeds, wholegrains, dark chocolate
Calcium	Triggers every muscle contraction; builds bones; helps blood clot and nerves signal.	Dairy, fortified plant milks, tinned fish with bones, tofu
Chloride	Works with sodium to balance fluids; used to make stomach acid for digestion.	Salt, seaweed, tomatoes, olives

General information, not medical advice. Speak to your GP before changing your diet if you have a medical condition or are pregnant.