The truth behind what you see on social media (including my own content).

Can you lose weight eating only junk? It sounds ridiculous, but we decided to put it to the test. For the next 30 days, I’ve convinced Brendan, my videographer, to eat only Mcdonalds every day to see if a weight loss diet that works really is as simple as calories in, calories out. Or, if the McDonald’s diet has consequences on his body and health that I never could’ve expected. To see the McDonalds diet effect on Brendan, he’ll not only be doing a DEXA scan to measure his body fat and muscle mass, but we’re also conducting pre and post-blood tests. We’ll also be testing Brendan’s strength before and after the experiment to give us another way to assess if he’s lost any of his hard-earned muscle and strength.

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But for now, it’s time to create a McDonald’s diet plan that'll help him lose weight. Based on Brendan’s current weight, he’ll need to eat a daily target of 2000 calories. But to avoid losing muscle and ending up weaker after the 30 days, he’ll also need to hit a bare minimum of 120 grams of protein. But Dr. Layne Norton explains that the diet may get monotonous after a while, which reduces satisfaction and adherence. So, using Layne’s advice, the meal plan I made for Brendan consists of 3 meals and 2 snacks per day. But rather than locking him into a strict meal plan, I gave him a few different options for each meal. He’ll be logging everything into our new BuiltWithScience+ app. So, as long as he stays within his daily calorie and protein targets, he can modify the meals however he likes.

However, as it turns out, not every healthy meal option I selected for his Mcdonald’s weight loss diet was available in Canada. So, he had to start getting creative — like making his own salad out of his wrap. Brendan also started complaining about his racing heart. Honestly, though, I don’t think Brendan’s racing heart has much to do with his new diet. That's because he’s not only been drinking extra coffee to help with his hunger, but he’s also pretty nervous about what this diet might do to his health. Almost every item on the McDonald’s item is full of saturated fat, highly refined, and stripped of pretty much everything that makes them good. As a result, aside from sodium, he’s not even close to getting even just 50% of most of his recommended nutrients every day.

On day 5, Brendan shared 2 common problems he ran into while eating McDonalds every day. He doesn't always get the order he requests, which means more calories. And he’s having some ... well, difficulties in the toilet. The recommended fiber intake for Brendan is about 35 grams a day. On his McDonald’s meal plan, however, he’s getting less than a third of this, barely reaching 10 grams daily. The “blockage” he’s experiencing has definitely made accurately tracking his weight loss a lot more difficult than anticipated. While Brendan was blaming his lack of progress on his low fiber intake, I wasn’t fully convinced.So I did some deeper investigation.
… and I came up with 2 reasons for why Brendan couldn’t lose weight eating only junk despite supposedly being in a calorie deficit. First, Mcdonald’s was severely under-reporting the calorie contents of their food. Second, the body absorbs more calories from a highly processed diet than a less processed one. So, with Brendan’s heavily processed diet, he may not be in the calorie deficit we initially thought he was, especially with the “hidden calories” that McDonald’s doesn’t seem to take into account. Which means… no more butter on his breakfast sandwiches and no sauces on his wraps and burgers.

So, what was the Mcdonalds diet effect on Brendan after 30 days? Overall, Brendan managed to gain 2 extra reps on his bench and pull-ups, and matched his deadlift strength although he forgot to wear wrist straps, limiting his strength. As for his blood work, The main things we’re looking for are his cholesterol levels, his HbA1c, which is the best blood marker for diabetes, his inflammation levels, and his liver health. Normally, all of these would be negatively impacted by a junk food diet. But what actually happened? Nothing. All his blood work stayed pretty much the same, which is surprising. It turns out weight loss alone is a major health booster and can “balance out” the negative effects you’d expect from a nutrient-deprived, junk food diet. Which now begs the question. What actually happened to Brendan’s weight, fat, and muscle mass? After only eating McDonald’s for 30 days, Brendan dropped 5lbs on the scale, lost three cm off his waistline and according to the results of his DEXA scan ... dropped from 23% body fat percentage to 22% BF. Ultimately, this shows fat loss really is a numbers game.

For every 10 people who try to get lean, only 1 of them will get lean and manage to keep their lean physique for good. Why? Because most people rely on quick fixes that eventually fall apart, instead of building daily habits that make fat loss stick. I’ve narrowed the answer to how to get shredded down to just 5 simple daily habits. By mastering these habits myself, I recently got down to 11% body fat, and getting lean felt almost automatic. In this video, I’ll show you how to do the same. No gimmicks, no fluff. Just real, research-backed methods to help you get a lean body and stay lean.

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Dr. Eric Trexler - @MASSResearchReview

How to get shredded habit 1: increase your energy flux. Turns out, the leanest people in the world often eat more calories while maintaining less body fat. Why? Those with a lean body are being more active, being less sedentary. And because of that, they're able to match their energy balance effectively even though they're on a higher calorie diet. But a “highly active” lifestyle doesn’t mean you’re doing a crazy amount of cardio every day. All the experts I spoke to emphasized the power of plain old walking and just getting enough daily steps in. So here’s what I do. I already lift weights 4-5 times a week. But I also make sure I’m taking at least 8,000 to 10,000 steps a day.

The second habit you need to get lean: self-monitoring. But with so many things you could track, how do you know what’s actually worth paying attention to? Rank 1 by a long shot is body weight. The second most important thing is macros because your macros, protein, carbs, fats, and then obviously calories derived from that are the real big working gears of your diet, and they're going to have a huge effect on your results. And then rank 3 is steps. Outside of doing them for a good health effect, they’ll also potentiate your fat burning a little bit. Another thing to look for is the way your clothing fits. But to avoid overwhelming yourself, start simple. Begin with just 1 habit: tracking your body weight. Once you’ve got that down, move on to tracking your nutrition.

But as powerful as those first 2 habits of getting lean are, you won’t see the results you’re after if you neglect sleep. Sleep is such a critical component of keeping muscle on your body and getting the fat off that it is what I call an absolute non-negotiable. But it’s not just about sleep quantity. Despite equivalent hours of sleep per night, Dr. Eric Trexler found that the leaner folks reported that they were less frequently feeling tired, sluggish, and sleepy throughout the day. So, you need to improve both the quantity and quality of your sleep.

If you're serious about achieving a lean physique, here’s what I’d recommend you do. First, try to stick to a consistent sleep schedule. Next, watch your caffeine intake, especially in the afternoon and evening. Next, figure out how much sleep you need by spending 1-2 months being consistent with your bedtime and letting yourself wake up naturally without an alarm. That’ll help you find your ideal sleep duration. And lastly, if your lifestyle makes it hard to get enough sleep at night, naps can be a game-changer.

But even with enough sleep, it’ll feel nearly impossible to get lean if you’re not eating the right foods. Start with a high-quality protein source. Think eggs, fish, yogurt, or chicken, roughly the size of your palm. Next, add 1-2 servings of fruits or veggies to most of your meals. These fiber, nutrient-rich foods will prevent you from getting hungry shortly after eating. Lastly, complete your plate with whole grains. Examples include potatoes, brown rice, oats, and/or healthy fats like avocado or nuts. Exactly what and how much you add here will vary depending on your calorie target for the day.

The final habit you need to achieve a lean physique: set goals with a hierarchy. The first layer starts with your why. This is your big-picture goal. Layer 2 is your what. Think of these like the categories that make up your transformation. For example, eating healthier and sleeping better. These goals give you direction but still leave room for flexibility. Layer 3 is the how. This is where you apply the habits we went through earlier to lay out your daily routine to achieve your big-picture goal. This shifts your focus away from the outcome, like “losing 20 lbs of fat”, to the daily process that will inevitably get you that result. 

Timestamps:
0:00 - Why Habits Are Key to Get Lean
0:38 - Habit 1: Increasing Energy Flux
5:40 - Habit 2: Self-Monitoring
9:00 - Habit 3: Sleep Quality & Quantity
12:47 - Habit 4: Build High Quality Meals
16:44 - Habit 5: Create a Goal Hierarchy

Can't grow your upper chest? Try this.

For the next few months, I’m going to see if I can use the best science-backed strategies for training and dieting to help Cam ditch the dad bod and get six pack abs for the first time in his life. So, if you want to learn how to get a six pack, this video teaches you everything you need to know — from the best six pack workout to the best six pack diet.

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On Day 1, Cam started out at 160 pounds and, according to a DEXA scan, 25% body fat. But to get visible six pack abs, he’ll need to get down to at least 15% body fat. Here’s the plan: instead of relying on exercise alone to achieve 6 pack abs, our priority is dialing in his diet. The first step was getting Cam to track everything he ate using our BuiltWithScience+ app. On average, he was eating about 2,600 calories a day. To shed around 1 pound of fat per week, we needed to bring that down to about 2,100 calories. But rather than completely overhauling his diet, I wanted to focus on strategic food swaps.

While Cam aims to get a six pack, focusing on ab exercises alone won’t cut it. When you’re in a calorie deficit, your body looks for energy, and without proper training, it can burn muscle along with fat. The result? A “skinny” look instead of a lean, muscular physique. To prevent that, we’re implementing a well-structured training program that targets all his major muscle groups. By broadening his back and shoulders, we’ll create that V-taper look to complement his 6 pack abs and achieve a truly aesthetic transformation.

And as for Cam’s progress with his six pack diet … With Cam now logging every calorie he was eating on the BWS+ app, he was staying right on track to achieving his 6 pack abs with a daily target of 2100 Calories, and his weight on the scale was quickly moving in the right direction. While this is a great start, getting down to 15% body fat means Cam will need to drop all the way down to 139 pounds. What about cardio? Think of it like the cherry on top. The weight tells your body to keep your muscles, the diet does most of the hard work of losing the fat, and the cardio can just help speed up the process. And rather than forcing Cam to do grueling cardio sessions he’d never stick to long term, I wanted to find something he actually enjoyed. Basketball.

But if Cam wanted to rely on cardio alone to lose the same amount of fat he’s been losing through his diet, he’d need to play nearly an hour of basketball daily. So, when it comes to fat loss, a combination of both is key. And in Cam’s case, it was just enough to speed up his progress toward achieving 6 pack abs without affecting his strength in the gym. 

In 90 days, Cam lost 11 pounds and shaved 3 ½ centimeters off his waistline. But he’s not quite at full 6 pack abs yet. He’s sitting somewhere around 18-20% body fat. And that’s perfectly fine. Getting lean and staying lean is a marathon, not a sprint. And because we’ve been taking a sustainable approach, Cam was eager to keep pushing to see just how lean he could get. It’s time to take things up a notch with my favorite science-based six pack workout to make his abs really pop.

As Cam’s journey to achieving six pack abs continued beyond 90 days, he kept getting leaner. But this is where most people hit a wall. They drop to under 20% body fat and then progress stalls. Why? Your metabolism adapts as you lose weight. Just 10% of your body weight can cause your body to burn up to 200-400 fewer calories per day. So when Cam first started, he needed to eat around 2,100 calories daily to lose a pound of fat each week. But now, after losing 15 pounds, we’ve adjusted his target to 1,900 calories to keep the fat loss going.

However, as Cam’s weight started dropping into the 140s, he noticed some side effects. He was more tired and had to go lighter (instead of heavier) in the gym. Here’s why. As you lose fat, your body produces less leptin. In response, your body cranks up hunger signals and tries to conserve energy by decreasing your desire to move. Which can also start to affect your strength in the gym. 

The point at which this starts to happen varies for everyone. But for most men, it begins at around 15% body fat, and for women, it is around 25%. As you get leaner, these effects intensify. That’s why getting shredded is not only incredibly difficult to maintain but can also become unhealthy. So after 150 days of Cam’s fat loss journey, we decided to stop his diet. The extra push to get full 6 pack abs just wouldn’t be worth it. The result? He went from 160 pounds to 143 pounds, and from 25.2% body fat to a lean 14.6% body fat.

It took time and patience, but that's the key to real transformation. Click below to use the same program Cam did to achieve his incredible transformation:
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My new app BuiltWithScience+ is finally here. Comment 2025 and I'll pick 10 lucky winners to get lifetime access for free!

If you want to build every major muscle with just 6 exercises, a full body split is the way to go. Full body workout plans not only boost growth by training each muscle multiple times a week, but new research suggests they might also enhance fat loss. Five years ago, I shared a full body workout routine. But new research and hands-on experience have shown me how to make it even better. Today, I’m bringing you the upgraded version: a full body workout plan that includes 3 workouts per week — with as few as 6 key exercises per workout. I’ll walk you through all 3 workouts in the full body workout program, breaking down each exercise with science-backed tips. And the best part? You can try this entire routine for free on my new app.

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Timestamps:
0:00 - Full Body Routine Overview
0:42 - Full Body Workout A
8:10 - Full Body Workout B
12:12 - Full Body Workout C
17:36 - Download The Routine

To kick off Workout 1 of our full body workout plan, we’ll target the upper chest with the incline dumbbell press for 3 sets of 8-12 reps. The incline dumbbell press is one of the best all-around chest builders. Next, we’re moving to the lower body with squats for 3 sets of 6-8 reps. Research shows they don’t just grow the glutes as effectively as glute-focused exercises like hip thrusts, they also strengthen and grow the quads, adductors, and even your lower back. Next we’re focusing on the mid and upper back muscles with the dumbbell chest-supported row for 3 sets of 8-12 reps. To squeeze out extra growth: once you’ve hit failure on your last set, try to get at least 3-5 more half reps in that bottom position. Next, the hamstrings. You'll want both a leg curl movement and a deadlift-type movement in your workout plan. Today, we’ll focus on the leg curl. And to finish off this full body workout, you have 2 options. If you're using dumbbells, perform a superset of lying incline dumbbell curls for the biceps, then go right into dumbbell overhead extensions shortly after. Repeat that for a total of 3 times. If you're using cables, you can do behind the body cable curls superset with overhead rope extensions.

Time for Workout 2 in our full body split. First up, the barbell bench press for 3 sets of 4-6 reps. Next, hamstrings with Romanian deadlifts for 3 sets of 6-8 reps. Then, lat pulldowns for 3 sets of 8-12 reps. Don’t forget: on your last set, push past failure by doing as many full reps as you can, then extend your set with 3-5 half reps in the stretched position to squeeze out extra growth. Next, 3 sets of walking lunges, aiming for about 6-10 reps per leg. To finish up Workout 2, we’ve got another isolation exercise superset with the side delts and abs. For the side delts, I’d recommend behind the body cable lateral raise with the cables set up 3-4 notches up from the bottom. After you’re done, we’ll immediately go into an ab exercise: reverse crunches. Repeat for a total of 3 times. 

Alright, that wraps out Workout 2 of our full body workout routine. Time for Workout 3. First, we have the seated dumbbell shoulder press for 3 sets of 8-12 reps. Next up, the dumbbell row, with 3 sets of 8-12 reps. Don’t forget. On your last set, push past failure by doing as many half-reps as you can in the stretched position to maximize growth. Next up, 3 sets of 10-15 reps of hip thrusts. An effective swap are dumbbell step-ups on a bench or platform. To finish off the quads for the week, we’re doing 3 sets of 10-15 reps of leg extensions. Next, we’re working the chest with 3 sets of 10-15 reps of flyes to compliment the pressing we’ve done earlier in the week. My preferred setup is a seated cable fly with a pad or foam roller between my back and the bench for a deeper stretch in the chest. Alright, to finish off the week, we’ve got our final isolation superset, starting with calf raises. For maximum growth, standing calf raises are the way to go. Once you’re done, move straight into reverse cable flyes to target the rear delts.

Repeat this superset for a total of 3 sets to wrap up your week of training (and week of full body workout routine).

Now, if you’re wondering how to track all of this or remember the form for each move in the full body workout program, BuiltWithScience+, my new app, is designed to do all the heavy lifting for you — except the actual weights, of course. It’s super simple. Just click on the exercise, and you’ve got the form video right there. You can even swap exercises if you’re missing equipment or have an injury, and the app will still make sure you’re still working the right muscles. Plus, it tracks your sets and even starts coaching you after the first week. It’s just like having me with you at the gym. You can try 2 weeks of it for free by simply heading to https://builtwithscience.com/app.

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After years of hiding this, it's finally here. I can't wait to share with you guys what I've been working on.

https://builtwithscience.com/

This is a big moment for me! It's a project I've been working on for years to help you with your fitness journey. I can't wait to share it with you. Don't miss out!

Here’s how your body structure affects what your squat will look like. What type of squatter are you? Comment below!