Unless you've been living under a rock these past few months, you can't have escaped the exponential rise of Joe Wicks, aka The Body Coach.
The 30-year-old Londoner is now a bone-fide online fitness guru - his social-media posts earning him legions of fans, who eagerly await his daily recipe and workout posts on Instagram (728k followers), Facebook (631k), Twitter (115k) and YouTube (65k subscribers).
Wicks started out as a personal trainer, but in just two years, he's built up a staff of 50, who help him manage the thousands of clients doing his online fitness programme.
Wicks' success is ultimately down to his savvy social-media presence: his #Leanin15 videos feature him throw together healthy meals in just 15 seconds, which he promises, when combined with his high-intensity interval training (HIIT), will leave you looking ripped - much like the man himself, whose baby-face features can't have hindered his soaring popularity.
Yes, business is booming for Wicks: his new recipe book, Lean in 15, has sold 320K copies in just four weeks.
He tells me he never imagined he would be so successful. "When I was building up my following [on social media], I never really had the intention to create a book or a business. It was just having fun, connecting with an audience, sharing my ideas."
Having followed The Body Coach online for some time myself and witnessing his amazing client transformations, I was sucked into the hype and signed up for his 90 Day SSS online fitness plan (the "SSS" is for "shift, shape and sustain").
According to Wicks, about 300 people sign up to the plan every day.
"One-hundred thousand people have signed up in two years," he says.
On forking out for the regime (approximately ¤192), a lengthy questionnaire promptly arrived in my inbox, requiring details of my health, diet and exercise habits. I was asked to send my weight and measurements, and to upload "before" shots of my body (cringe), so my progress could be tracked throughout the 90 days.
As well as following Wicks's diet, you're required to work out four times a week. You can follow Wicks's fitness regime - which involves HIIT, German Volume Training (GVT) and Dramatic Transformation Principle (DTP) training - or opt to do your own, which is what I did: I wanted to be able to incorporate the programme into my lifestyle long after the 90 days were over. I cycle 13km to work, circuit train and go to dance class regularly - I'd keep this up throughout the plan.
A few days after filling out the questionnaire, I received Cycle One of the programme - my handbook for the next 30 days - and assigned a personal trainer who would support me throughout the plan via email.
The Body Coach team designed a tailored food programme for me: I would be eating three meals and two snacks a day. The fat, protein and carbohydrate content of my meals were carefully constructed to suit my body composition and activity levels.
Wicks admonishes severe calorie restriction, teaching that fat loss can only comfortably occur when the body's energy demands are met with a small calorie deficit, paired with specific macronutrient timing.
Cycle One is all about shifting excess fat so most of my meals were low in carbhoydrates and high in protein and fat; carbs were only included in post-workout "refuel" meals.
The recipes, which included 'Overnight Protein Oats', 'Teriyaki Salmon' and 'Spinach and Feta Omelette' were really tasty. I spent a couple of hours every weekend cooking in bulk so my meals were ready for the week ahead - preparation is key.
I couldn't believe how much I was eating at the start, but as I neared the end of the first 30 days, my appetite grew and I found myself feeling hungry more often - a sure sign that my metabolism was speeding up. The high fat and protein content of my meals was nauseating initially, but my body soon adapted.
"Girls and boys are so programmed to thinking that to burn fat, you've go to really drop calories and do an hour in the gym, two hours in the gym. But I'm teaching that you can eat a lot more food - and the same thing always comes up, 'Is this too much food?', 'How can I be possibly burning fat?', but because of the macronutrients, your body loves it and it burns fat," Wicks explains.
"So, it really works," he added. "It's not charm - it's not luck that 100k people have signed up. I know I'm good on social media, but the fact that it works... people commit to it."
Wicks seemed to be right: at the end of this cycle I had lost inches, while gaining a kilogram - Wicks warns clients to stay off the "sad step" (ie. weighing scales), and says the focus should be on inches lost, muscle gained and energy levels.
At this point, my energy was up, my skin was glowing and my sleep quality had improved so much. My colleagues even start to compliment me on how well I was looking. Winning!
A few days after submitting my Cycle One results, Cycle Two arrived in my inbox, complete with new dieting rules and a whole new set of recipes. In this cycle, you can get creative, making your own meals using Wicks's pick-and-mix principles.
The next 30 days were about building lean muscle, which involved huge portions of bread, pasta, rice and oats on training days. It was a month-long carb-fest. But, although I had a lot more energy, I felt bloated constantly. However, on submitting my progress photos, I realised I had toned up considerably. Result!
Sixty days down, 30 to go.
The aim of Cycle Three was to burn more fat while sustaining the muscle gained in the previous cycles. It came with more new recipes, and considerably smaller portions. Recipes included a 'Tuna Melt' and 'Super Lean Beef Burger'.
I started this cycle just before Christmas, so gave myself a few days off-plan for the holidays. On consulting with my coach, I decided to add this time off to the end of my plan.
This cycle was the toughest, both mentally and physically: my appetite was huge and motivation seriously waning. I often felt lethargic, which made my workouts harder. Despite this, I experienced more inch loss, but at this stage of the game, I was counting down the days until the end...
Now, having just completed the plan, there's been definite changes to how my body looks - just not as much as I'd expected. But my metabolism is faster, I'm eating more and am now equipped with valuable knowledge on macronutrient timing.
For these reasons, I'd recommend the 90-day regime, however, be warned: your social life will definitely be compromised while on the progamme. Strictly speaking, you should be teetotal throughout, but I allowed myself a few 'cheats' for Christmas parties and a handful of nights out.
I usually eat out a lot, but cut down on this greatly so as not to deviate from the plan. What I found most challenging was the macronutrient timing - if I wanted to go to a restaurant to enjoy meal, I'd have to schedule in a workout beforehand.
"The plan works for people who are willing to commit to it. So, if you see people doing it half-heartedly, they're going to get half the results," Wicks tells me.
"People who really commit to it and follow it and really give it 100pc, they're the ones that end up in the 'Hall of Fame'."
I certainly won't be making Mr Wicks's "Hall of Fame", and like he says, my results would have been more dramatic if I banned alcohol completely and stayed on course over the festivities... but a girl's got to have her fun too!