Underground Fat Loss Manual Review – UPDATED – Gimmick Or Genuine?

UPDATED – The Underground Fat Loss Manual is an unconventional fat loss program promoting quick fat loss for best results instead of the usual slow and steady traditional method.

Like a band-aid stripped off quickly, a fast track to fat loss seems to be a better solution than a slow and painful plan, at least according to the author.

Matt Marshall provides due scientific references to case studies from authoritative sources to support his claims, as well as eloquent testimonial pictures and videos.

None of Matt Marshall’s programs are conventional, both in the fat loss or muscle building arenas. With his brand Fitness Under Oath, he is building a reputation for unorthodox but effective methods, steadily building a solid following.

While his muscle-building program “How To Build A Classic Physique” (you can read the review here) stems from tested and proven old-school training strategies from a bygone era, the Underground Fat Loss Manual takes novelty up to a whole new level.

While “How To Build A Classic Physique” is mainly based on old and proven workout methods forgotten and repackaged together by Matt in a viable format, The Underground Fat Loss Manual is new. It is unlike any other fat loss plan you may have come across.

Underground Fat Loss Manual
If you think that slow-and-steady is the only way to go, think again, for this is not a small-calorie-deficit program.

Yet it is not a crash diet fad either, for there is a method to these rapid fat loss results: they encompass all aspects of nutrition, including macros, timing, and the addition of unusual, unconventional tips (albeit a bit borderline, but nothing illegal).

It is also confidence-inspiring that the author even offers a 60-day money-back guarantee with its program, should you not be satisfied for any reason.

Keep reading the review because this will be as weird and interesting a plan on losing fat as you may not have come across before, ever.

Review Update

2021 UPDATE – The Underground Fat Loss manual has been recently updated to include 4 more bonuses and an expanded book on the controversial “Chapter 13” of the original manual, where some controversial fat loss techniques are discussed, for a total of 5 new items on top of the original manual.

The is a breakdown of the new package offered by Matt Marshall –

Underground Fat Loss Manual Chapter 13 1 – The Banned Chapter 13 – This is a dedicated booklet in which Matt reveals all the underground secrets of top fitness models and world-famous personal trainers that he has been forced to remove from the main manual because too extreme for a mainstream audience.
Some of these underground techniques are:

  • A morning drink that can boost your body’s calorie-burning capacity by 16%
  • High sodium foods that kill hunger cravings and help you reduce your calorie intake.
  • “Adult” beverages that accelerate weight loss.
  • A particular chewing gum that helps you shed pounds.
  • A homemade stack that helps you in your weight loss journey.

Underground Fat Loss Manual 12 Minute Per Week Workout Plan 2 – The 12-minute Per Week Workout Plan – This is as minimalist as it gets a workout plan. If you are strapped for time, it comes in very handy. Inside, step-by-step instructions on workouts.

3 – The Quick Start Guide – This is like the Underground Fat Loss Manual distillation. If you don’t have the time to go through the whole lot before starting, then this booklet serves you right for the purpose, enabling you to get down right away.

Underground Fat Loss Manual Cheatsheets 4 – The Cheatsheets & Accountability Log – A 21-day tracking sheet log to keep you motivated, helping you visualize your progress as you go along.

5 – Private Members’ Social Group – A social community for Underground Fat Loss Manual members where they can ask questions and support each other. This bonus is by no means compulsory, you join only if you want to.

Finally, the $100 monthly price competition is still going. Get the Underground Fat Loss Manual, make some before and after pictures, send them to Matt after completion of the 21-day timeframe. The best result will win the prize.

Underground Fat Loss Manual

The Ideal Candidate For This Program

The Underground Fat Loss Manual was designed for those who may have tried losing fat before with partial success but eventually failed because of the long, tedious and unsustainable nature of whatever their plan was.

For extended periods, mild calorie deficits seem to be the proven path for a steady and safe fat loss. And it is. It does work. However, the reality of such an approach often results in tedious calorie counting and meal planning that has to be adhered to for ages and adjusted along the way as you get leaner.

As often is the case, people stray from such fat loss plans or give up altogether, soon relapsing into their old over-weight self. Yet still, they are afraid of jumping in too fast with an aggressive calorie deficit for fear of the typical crash diet’s disastrous effects, like slow metabolism and muscle depletion.

The Underground Fat Loss Manual offers an alternative to both paths in that it allows you to tackle your fat loss task in a more aggressive but controlled way than the slow and steady way of old, but without the adverse side effects of typical crash diets.

This program is therefore suitable for those who want to try a different method that could yield results fast and motivate them to stick to their plan, but were so far being put off by the negative side effects associated with typical crash diets.

Underground Fat Loss Manual Review

What Makes It Different?

For a start, this plan advocates more freedom than conventional fat loss plans.

Whereas in regular plans, cheat meals are allowed but strictly monitored, the Underground Fat Loss Manual lets you eat as many as three cheat meals per week once you reach your ideal weight.

Chocolate and wine are allowed, and the author even reveals a controversial way to have alcohol aiding your fat loss if taken in a specific way. A bit borderline but worth mentioning.

As borderline are the nicotine chewing gum and baby aspirin tips as extra aids for fat loss. These are known methods that have been tried before, but to be honest, not the healthiest or sustainable in the long run.

However, these are not what the program is all about, just additional weird tactics that may or may not be implemented at discretion. The foundation of the program is more robust. Here we go.

How Does Underground Fat Loss Manual Work?

This is a digital program with a central manual and several bonuses. The plan’s starting point should be an accurate body-fat assessment with a DEXA scan, which is more accurate than most other methods but also more expensive.

A DEXA scan to determine your body fat percentage can cost an average of $60 per year if checked monthly, but it gives a more realistic assessment of your actual body fat, typically more than one may expect.

However, do not let this premise put you off, as you can resort to good old cheap skin calipers from your local store.

Once you know your body fat, you are given a 4-week protocol, followed by a maintenance phase. This is the same protocol Matt Marshall used to lose 13 lbs of fat in 30 days, and here is a breakdown of the main topics:

  • An excursus on a regular diet, bodybuilding diets, and the Underground Fat Loss method, points, and differences.
  • First 3 Days.
  • Days 4-13.
  • Day 14: The Cheat Day.
  • Days 15-28.
  • Maintenance Mode.
  • Advanced Tips.
  • Foods For Fat Loss.
  • Hunger.
  • Muscle Loss, Testosterone Loss.
  • Family, Friends, And Other Obstacles.
  • Final Words.

Even though the schedule is short and straightforward, it is not easy. It requires determination and a willingness to stick through it, particularly in the beginning, the crucial first three days, where you can expect a substantial fat loss, which is a bit of a shock.

These phases are not just about calorie restrictions mixed up with cheat meals but give precise instructions and practical day-by-day directives about what to do, what to eat, and when.

Originally designed to burn off remaining fat from people in good shape, the Underground Fat Loss Manual has been used by out-of-shape men and women to lose much more than that.

Some customers have lost 20/30 lbs of fat or more, as shown by the testimonials’ photos unique to this program.

Underground Fat Loss Manual

Scientific Studies Supporting The Manual

The boring stuff, but it had to be done to verify the authenticity of Matt Marshall’s claims, given their eccentricity. So, we found the links to these studies for you to check out.

The first study Matt puts forward is this one from the University of Newcastle by Prof. Mario Siervo, proving that out of 3 different groups of obese men, the one that experienced LESS reduced metabolism was the one that also dieted the hardest for the shortest time. In contrast, the slow-and-steady group experienced the most significant drop in metabolism.

The second study is from a team of researchers who found out that slow and steady, small calorie deficits elicit a slow metabolism, resulting in increased fat mass,  decreased lean mass, and decreased energy expenditure (in simple terms, fewer energy levels).

The third study is particularly revealing of the adverse effects of slow dieting on males. This study by Fontana L, Klein S, Holloszy JO reveals that slow dieting on moderate calorie restriction for a long time causes a drop in testosterone of up to 78%.

The fourth study Matt provides is this one from another group of researchers. This study is probably the most surprising because its results point to the fact that those people who dieted the hardest for the first eight weeks are also those who keep the weight off more quickly afterward.

This is a table-turning study that seems to dispel the standard consensus that crash diets are the ones that cause yo-yo rebounds while opening up a new, unexpected scenario.

According to this study, crash diets, or aggressive diets, seem to elicit better long-term returns than cautious, conservative, small-calorie-deficit diets.

So here we go; when you thought you had a good idea of what works for losing fat, new evidence throws you off your pedestal of certainty.

Food for thought.

About Matt Marshall

Matt Marshall Matt Marshall is an unconventional author of several fitness programs on fat loss and muscle building and the Fitness Under Oath brand founder. He is also a certified personal trainer.

His program claims to be an underground, off-the-mainstream fitness expert with a dislike for extensive social media presence and a reputation for unusual training and dieting methods.

His methods are more niche-oriented and intended for those looking for something different from big brand workouts or flash-in-the-pan weight loss programs, but simple and effective.

He is also a contributor to stack.com, where you can read some of his interesting articles. Among his programs, The Underground Fat Loss Manual reviewed on this page and How To Build A Classic Physique, reviewed here.

Matt’s New Fat Burner Supplement

As recently as March 2021, Mat Marshall has also released a new supplement called “The Underground Fat Burner.” It is a water-soluble supplement that you mix with a  glass of water rather than gulping it down like a pill or capsule.

This is because Matt reckons this is the best way for the active ingredients to take effect. The product is all-natural and non-GMO,

Each dose is formulated to curb unhealthy appetite, such as snack cravings, while maximizing fat burning and make it easier to reduce your body fat. For a chance to have a peek and see how this new supplement works, click here.

You can read my full review of the Underground Fat Burner supplement here.

Underground Fat Burner
==>Underground Fat Burner Website<==

Underground Fat Loss Manual Components

The program is digital, instantly available through a download and comprises 1 main component and several bonuses, plus it comes with a 60-day money back guarantee. Here is what you get:

The Underground Fat Loss Manual PDF – The 104-page main manual with all the theory and action plans for this unique fat loss blueprint.

The Bonuses

The 10-3-X Workout Program – A custom workout program put together by the author himself, unique and not rehashed from other programs. It is challenging enough and simple enough to be done at home with essential gear or at your gym.

The 60 Second Hormone Fix – A simple strategy to naturally reset hormonal imbalances, regulating insulin and leptin to boost metabolism and promote fat loss.

Ageless Abs Manual – A booklet pinpointing what the author claims to be the single most effective ab exercise performed by veteran athletes who still show a six-pack well into their 50s and 60s. One that is easy on the spine too.

Personal Email Address And Cell Phone Number – This one is unique. Matt Marshall offers his contact for clarifications and help, at least for now. Should the program become super popular, he may need to remove it.

$250 Cash Reward – Again, Matt Marshall is not the usual fitness author out there. His program comes with an enticing cash prize, once every month, for whoever can show the best body transformation by following his plan. Here is how it works:

  1. Buy the program.
  2. Read It.
  3. Take a “before” snap.
  4. Put the plan into action.
  5. After 60 days, take an “after” snap with all your stats and send all materials to him.
  6. Each month he reviews all the submissions, and the best one wins $250 cash.

Underground Fat Loss Manual

>>Click Here To Visit The Underground Fat Loss Manual Official Website<<

Any Testimonials Yet?

Despite not having been around for a long time, The Underground Fat Loss Manual has already collected an impressive list of testimonials with eloquent before/after pictures.

All the testimonials and results of the program are genuine, authentic, and unique and not taken from some stock photos or other websites, as sometimes authors of dubious programs do.

So kudos to Matt for putting together a program that has already helped many men and women with bodyweight problems in such a small time frame.

Underground Fat Loss Manual Testimonials

Positive And Negatives Of The Program


  • Unusual and alternative weight loss program.
  • It does not require you to work out unless you want to.
  • Quick solution for fast weight loss.
  • Ideal for people who find it challenging to stick to slow, long-term plans.
  • Cheat meals are allowed and part of the weight loss plan.
  • New, private members’ area for support.
  • 60-day money-back guarantee.


  • Underground Fat Loss Manual should be used as a one-off, then followed by a controlled, calorie-balanced diet for maintenance.
  • Not available in physical format.

My Opinion On This Program

I think the Underground Fat Loss Manual can be the right solution for those who tried losing weight before but failed because of the inherent difficulty of sticking to a weight loss plan for the long term.

Suppose long-term discipline is an issue for you. In that case, this plan allows you to shed unwanted fat in a fraction of time by strategically implementing calorie restriction with cheat meals and unusual tactics.

It is not a crush-diet kind of thing, but rather a controlled fast weight loss for a short time, which is more feasible for those having trouble with the slow, steady method.

It also gives you a workout blueprint to keep fit and accelerate the process.

However, I also think that once the program is over, you should stick to a healthy, calorie-balanced diet with all the macros in the correct ratio and avoid gaining and losing weight again and again.

The Underground Fat Loss Manual should be used once as a precursor to a healthier lifestyle and more balanced nutrition habits and not as a fall-back trick to use whenever you gain weight.

Once you lost your unwanted fat, make sure to keep your body weight in check and be disciplined.

Conclusion On The Underground Fat Loss Manual

Without a doubt, the Underground Fat Loss Manual is what is says on the tin: an under-the-radar fat loss plan that goes against the mainstream plethora of programs out there.

Far from advocating a mindless crash diet, the programs revolve around a planned and controlled rapid fat loss with a daily schedule, cheat meals, and some extra gray-line fat loss tips that may or may not be adhered to.

The basis of this approach is that faster is better when it comes to fat loss, and the author provides plenty of scientific references for support.

That does not mean crash dieting for sustained periods with a substantial calorie deficit without a break. This counterproductive approach leads to yo-yo rebounds, slow metabolism, and muscle depletion.

The author discusses a calorie deficit strategically implemented with cheat meals within a timely schedule that works better than the old slow-and-steady approach. He even offers a 60-day money-back guarantee, should you not be satisfied for any reason.

To sum up, if traditional methods have failed you before, this unconventional plan may be an alternative solution to ponder, particularly considering the real-life testimonials and the enticing prize offered by the author.

Underground Fat Loss Manual

Underground Fat Loss Manual FAQs

 Any side effects using Underground Fat Loss Manual?

Underground Fat Loss Manual in an unusual fat loss protocol in that it promotes quick fat loss as opposed to moderate fat loss in the long term. This may be fine if you are young and fit, but it may not be ideal if you are not young anymore or have some medical issue. Always consult your doctor for advice first.

How do I know if the Underground Fat Loss Manual is right for me?

Choosing the right product is the the most difficult part of your search. We recommend doing extensive research and cross check customers’ feedback and other reviews from different sources in order to make an informed decision.

 Does Underground Fat Loss Manual work?

Underground Fat Loss Manual has already accrued a vast catalog of satisfied customers as showcased by numerous original testimonials. However, everyone is unique and results may vary.

What is the price of Underground fat Loss manual?

Right now, the plan comes at $14.95.

Where can I buy the Underground Fat Loss Manual?

You can get it only at the official website here.

Can I return the plan if it is not for me?

Yes you can. Underground Fat Loss Manual comes with a 60-day money back guarantee.


From the author of the Underground Fat Loss Manual, a complimentary supplement in powder form has just been released – The Underground Fat Burner Supplement.

The Underground Fat Burner Supplement

=>>Click Here To Check It Out<==

==>Or Read My Review<==

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