Mike Matthews shows his flexible-dieting method in a real client case study. Here's how to run that same system across your whole roster.
This video isn't a macro lecture - it's a coaching case study, a client losing weight over 24 weeks, with Matthews' flexible-dieting approach doing the work underneath: calorie and protein targets, food freedom instead of banned lists, and a deliberately unhurried ~1 lb/week pace. This breakdown covers that method in our own words, adds our honest take for a coaching business, and shows how to template it once and reuse it for every client.
By Markus Evers · September 2026 · a Coachway video breakdown
the short version
The video is a client case study, not a methodology explainer - but it puts Matthews' flexible-dieting approach on display: hit calorie and protein targets with food freedom (no banned foods), keep the pace sustainable at roughly a pound a week, and adjust only from multi-week trend data. The one thing a coach should take from it: run one repeatable, numbers-based framework for every client instead of a bespoke restrictive plan each time - and let the trend, not a single scale reading, tell you when to change it.
Mike Matthews - How My Coaching Helped Matt Lose 24 lb. in 24 Weeks
Source: Mike Matthews (Muscle for Life) on YouTube - "How My Coaching Helped Matt Lose 24 lb. in 24 Weeks". Watch on YouTube. We embed the public video and summarise it in our own words; the video, title and channel belong to Mike Matthews, and nothing here implies his endorsement of Coachway.
Who is Mike Matthews, and why coaches watch
Mike Matthews is the author of Bigger Leaner Stronger - one of the category-defining natural-fitness books - the voice behind the Muscle for Life brand, and the founder of the supplement company Legion. His whole platform is built on a simple, unglamorous promise: flexible dieting plus basic progressive-overload training, run consistently, beats complicated plans that people quit. For coaches he's a useful reference precisely because he's not chasing novelty - his method is the boring, repeatable framework a coaching business can actually deliver at scale. This page reads him through that lens: not "should I copy his program," but "what does his flexible-dieting system mean for how I run a whole client roster."
What the case study shows (our summary)
This is our summary of the flexible-dieting method the video demonstrates, in our own words - not a transcript. The video is a client case study, so watch the original for the actual story, and note that the only figure it states is the "24 lb in 24 weeks" of its own title.
- 1
Targets, not food rules. The engine of flexible dieting is a daily calorie and macro target - protein first - rather than a list of allowed and forbidden foods. The client's job is to hit the numbers; the food choices are theirs.
- 2
Food freedom protects adherence. No banned foods - typically framed as roughly 80% whole foods and 20% flexible. That flexibility is what keeps a diet liveable over months instead of days, which is the real reason the pounds actually come off.
- 3
A sustainable pace, on purpose. The case study's own headline - 24 lb across 24 weeks, roughly a pound a week - is the method in one line. A moderate deficit protects muscle and energy and is far more repeatable than a crash.
- 4
Simple training underneath. Matthews pairs the diet with straightforward progressive-overload work on compound lifts - add a little load or a rep over time. The nutrition drives fat loss; the training protects the muscle you're keeping.
- 5
Adjust from the trend, not the day. Bodyweight bounces daily. His consistent position is to change intake only when a multi-week average genuinely stalls - which is exactly what a 24-week arc is built to reward.
Coachway's take
We're firmly on board with the core system, and it's the one most new coaches under-use: flexible dieting is a framework you can run for almost any client, which makes it the right default for a business rather than a one-off restrictive plan you rebuild from scratch each time. Set calories, anchor protein, give food freedom, hold the pace - the structure barely changes from client to client. That's not a weakness; it's what lets you coach twenty people well instead of five people frantically.
Where we'd add nuance: the honest lesson of a case study like this isn't the macros - it's the 24 weeks. The number that matters is the calendar, and the coach's real job across those months is expectation-setting and adherence, not clever programming. Most clients don't quit because the plan was wrong; they quit because week six felt slow next to a two-week transformation they saw online. Setting the ~1 lb/week pace at kickoff, and then defending it every check-in, is where the results actually get made.
The other coaching-specific point: "no banned foods" is a promise you have to manage, not just announce. The 80/20 framing only works if the client understands the 20% is the buffer that keeps them sane, not the base of the diet. In practice that means anchoring protein and whole foods first and treating the flexible slice as the last thing that gets filled - otherwise "flexible dieting" quietly becomes "eat whatever fits and wonder why hunger and recovery fall apart."
So our version of his approach is: run one flexible-dieting framework for the whole roster, set a realistic pace out loud on day one, adjust only from the two-to-three-week trend - and build the whole thing as a reusable template so a new client is a five-minute setup, not an evening of macro maths.
Set the targets once, then coach the trend
Flexible dieting only scales if you can set targets fast and read progress honestly. That's what Coachway's meal planner and macro tracking is for: set each client's calorie and protein targets, let them log food daily against those numbers, and keep the 80/20 balance visible instead of guessing why a client "can't stick to it." Then client progress tracking gives you the weight, photo and measurement trend - so when you decide whether to move calories, you're reading a two-to-three-week average, not one bad Monday. That's the whole method in software: targets on one screen, trend on the next, food freedom in between.
If you want the strategy layer first, our guide to flexible dieting covers the framework in depth, and the walkthrough on how to adjust a client's calories after two weeks covers the trend-reading half of the same job - the decision you make once the logging has given you real data.
Start your 14-day free trialFlexible dieting starter (client setup)
A fill-in setup you can copy for any client. Work top to bottom: set calories from bodyweight, anchor protein, set fat, then let carbs fill the rest. The multipliers below are standard flexible-dieting starting points and our coaching defaults - a place to begin and then adjust from the client's own trend, not figures quoted from the video.
Flexible dieting starter
Set the targets (starting points)
| Target | Starting-point formula | Your client's number |
|---|---|---|
| Calories | Fat loss: bodyweight (lb) × 10-12 · Muscle gain: × 16-18 | — |
| Protein | ~1 g per lb of bodyweight | — |
| Fat | ~0.3 g per lb of bodyweight | — |
| Carbs | Fill the remaining calories | — |
Run the plan (daily + adjust)
| Rule | What it means in practice |
|---|---|
| Hit calories + protein daily | These two non-negotiables drive the result; carbs and fat flex around them. |
| ~80% whole / ~20% flexible | No banned foods - fill whole foods first, keep the flexible slice as the buffer. |
| Set the pace out loud | ~0.5-1% of bodyweight per week; slow is the plan working, not failing. |
| Adjust from the trend | Change intake only after 2-3 weeks of trend data - never off one scale day. |
How to use it: set the four targets at kickoff, hold the client to calories and protein daily, and review the 2-3 week weight trend before touching anything. The multipliers are starting points - the client's own data, not the formula, decides where the numbers settle.
FLEXIBLE DIETING STARTER (via Coachway) - client setup, standard starting points / our coaching defaults, not figures from the video SET THE TARGETS (starting points) Target Starting-point formula Your client's number Calories Fat loss: bodyweight(lb) x 10-12 | Muscle gain: x 16-18 Protein ~1 g per lb of bodyweight Fat ~0.3 g per lb of bodyweight Carbs Fill the remaining calories RUN THE PLAN (daily + adjust) Rule What it means Hit calories + protein daily The two non-negotiables that drive the result; carbs and fat flex around them. ~80% whole / ~20% flexible No banned foods - fill whole foods first, keep the flexible slice as the buffer. Set the pace out loud ~0.5-1% of bodyweight per week; slow is the plan working, not failing. Adjust from the trend Change intake only after 2-3 weeks of trend data - never off one scale day. HOW TO USE: Set the four targets at kickoff, hold the client to calories and protein daily, and review the 2-3 week weight trend before adjusting. The multipliers are starting points - the client's own data decides where the numbers settle.
Flexible dieting for clients - FAQ
What is flexible dieting (IIFYM)?
Flexible dieting is the approach Mike Matthews built his coaching on: instead of a list of 'good' and 'banned' foods, the client hits daily calorie and macro targets - protein first - and has real freedom in how they fill the rest. No food is off-limits, which is why it tends to hold up better over months than a rigid clean-eating plan. The coaching skill isn't the food rules, it's setting the targets correctly and holding the client to them. For a coach, that's the appeal: one framework you can run for almost any client, adjusted by the numbers rather than by willpower.
Does flexible dieting mean a client can eat junk food and still lose weight?
In a literal energy-balance sense, weight is driven by total calories - so yes, a client can technically lose fat while fitting some treats in. But that misreads the method. Matthews' version is usually framed as roughly 80% whole, nutrient-dense food and about 20% flexible, precisely so protein, fibre and micronutrients don't collapse and hunger stays manageable. The '20%' is what keeps the diet sustainable, not the point of it. As a coach, the honest framing for clients is: food freedom is how we protect adherence, not a licence to build the diet out of the flexible slice.
How fast should a client realistically expect to lose weight?
The case study in this video is a useful anchor: its own title documents 24 lb over 24 weeks - which works out to roughly a pound a week. That pace is the whole point. A moderate deficit protects muscle, energy and adherence, and it's far more repeatable than an aggressive crash that a client abandons in a month. The coaching move is to set that expectation at kickoff, before the client compares themselves to a two-week social-media transformation, so slow-and-steady feels like the plan working rather than the plan failing.
How often should you adjust a client’s calories?
Matthews' consistent public position is to adjust from the trend, not from a single reading. Bodyweight bounces daily on water, sodium, sleep and digestion, so one heavy scale morning is noise, not a signal. The practical rule most coaches land on is to look at a 2-3 week average before changing anything - if the trend has genuinely stalled against the goal, then you move calories or activity. As a coach, that patience is half the job: it stops you chasing the scale, and it stops the client panicking when the number wobbles.
More nutrition-science breakdowns
- · Layne Norton on diet adherence - why the plan a client sticks to beats the "perfect" plan they quit.
- · Sohee Lee on sustainable fat loss and adherence - the pace and behaviour side of the same method.
- · The full roundup: fitness YouTubers coaches should study.
Keep dialing in nutrition coaching
all guidesFlexible Dieting (IIFYM): What It Is
Flexible dieting (IIFYM) means hitting daily macro targets from any food. What it is, how it works, pros and cons vs rigid meal plans, and how coaches use it to build client adherence.
Read the guideMacro coaching: how to set, track and adjust client macros
Macro coaching means coaching to targets, not a fixed menu. How to set client macros from energy needs, match tracking depth to each person across four tiers, adjust on a two to three week check-in cadence, and run the whole loop without spreadsheets.
Read the guideHow to Adjust a Client's Calories After Two Weeks of Data (2026)
The two-week protocol: the five inputs, a worked weekly-average example with fourteen weigh-ins, the six-outcome decision table with the size of each change and its source, six reasons to hold, three client messages under 60 words, and a ChatGPT prompt that formats the data without deciding.
Read the guideFree tools for this: Keto Macro Calculator · Body Recomposition Calculator 2026 · Creatine Dosage Calculator
Run one flexible-dieting system across every client
Flexible dieting only scales if you can set targets fast and read progress honestly. Coachway lets you set each client's calories and protein, have them log food daily, and watch the weight trend - so you adjust from a two-to-three-week average, not one bad scale morning. Start your 14-day free trial and set up your first client's targets in minutes.
