|Dr. Mel Davis, PhD
Know someone who’s fasting to lose weight? Following a social media celeb who swears by swearing off carbs? Or counting macros or calories? Or maybe you're no stranger to RP's diet philosophy. Let's compare these options and evaluate each for its weight loss merit. If you're just getting to know RP, here's an intro to our diet approach:
READ MORE about dieting and training in quarantine to keep gains coming while locked down.
Good news: all effective diets adhere to one or more of a few basic principles. Some principles contribute more to results than others as shown in this pyramid:
Let's start with the most important one: calorie balance. This dictates that, in order to lose weight, you must take in less energy than you use. This is what forces your body to break down its tissue to make up the difference. Without a calorie deficit, weight loss cannot occur. Moreover, when a calorie deficit is in effect, weight loss will always occur. While certain health conditions make it more difficult to eat less or burn more, anyone who manages to intake less energy than he or she uses will lose weight, hormonal or other conditions notwithstanding. All successful weight loss diets require a deficit.
Diets can work via counting calories to achieve a deficit: calories in, calories out, or CICO. They can also work by creating a deficit indirectly, by restriction of eating windows (intermittent fasting) or elimination of food items or groups (low carb or paleo diets for instance), all of which can result in deficits.
If you only focus on calories, however, you might not get the body composition changes you seek. Most of us would like to end a weight loss diet looking firmer and leaner, not smaller but softer, aka “skinny fat”. The latter result comes from losing muscle along with fat on your diet, which is easy to do if you are not paying attention to other principles of body composition change. This is where macro counting, the next key principle, comes in.
For those new to this stuff, macros are just the main nutrients (short for "macronutrients") that contribute to almost all of our daily calories: protein, fat, and carbohydrates. So, when you count macros, by default, you end up counting calories as well. As a bonus to weight loss, getting enough daily protein helps prevent muscle loss... along with that dreaded “skinny fat”. Getting enough fat (though minimums can be pretty low) maintains healthy hormones and vitamin absorption. Carbs are great for sport performance and fueling effective workouts, and, while not mandatory for a healthy diet, neither is avoiding them. When losing weight, after protein needs and fat minimums are met, you can eat carbs too, provided you stay under your daily calorie deficit ceiling.
Before we go on, let's pause here to appreciate the fact that about 80% of improved body composition can be had with just these two core principles: first, a caloric deficit, and secondly, good macros.
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The next few principles can help, but only by a small margin, so, unless those marginal gains are important to you, a lot of us can save ourselves further complexity on our weight loss journey. Calorie and macro counting can be done using intermittent fasting, IIFYM, RP Simplified Diet Templates, keto, or low carb diets. All of these diet strategies can work when they facilitate a calorie deficit, and good macro choices are made.
So how to choose? The key is to find what will be sustainable for you. A very important question to ask yourself is: when my diet is over, will I have created healthy habits that I can continue through maintenance (once no longer losing but staying at/around my new weight)? By definition, when your diet is over (aka, when you shift from fat loss to maintenance), you will increase your macros, and therefore calories. Beyond this increase, however, your general diet - the types of foods you eat and when you eat - should stay largely the same. So, it's important to consider which diet strategy will be comfortable for you long term.
If health is a consideration, food composition - sweet potato and almonds versus a donut to get your fat and carbs - becomes important. As such, IIFYM will no longer work for you, and the carnivore diet is also probably out. There is also some evidence that “healthier” food choices, in addition to being health promoting and more satiating, can result in slightly better body composition changes as well. Not to mention the fact that long term health is a prerequisite for fitness!
If you want to take your results up a notch, it’s time to take a look at the other, more minor principles for body composition change. You might be able to eek out another 10% worth of results by paying attention to nutrient timing. This is where intermittent fasting goes out the window, as meals need to be timed around training, and spread out more or less evenly over the course of the day. Finally, supplements such as protein powders, caffeine, creatine, and simple sugar drinks for training can add around 5% more icing to your results cake.
When choosing a diet, consider your current habits and lifestyle, to be sure you're choosing a level of detail you can feasibly manage, and a sustainable structure that suits your lasting preferences. If you can better adhere when keeping it simple, just stick to calories and macros and try to choose health promoting food options (lots of whole foods, plenty of plants). If you are up for the challenge long term, and want the absolute optimal results, pick a diet that hits all five principles represented in the chart below. And remember: the only diet that works is the one you can stick with, and weight loss is only maintained when sustainable habits are practiced through all diet phases (including, duh, maintenance... which is everything that comes after you've successfully lost the weight you wanted to)!
A quick disclaimer that lifting weights in parallel with dieting will prevent muscle loss. We cannot emphasize enough how important this is for both long term health and aesthetic changes! Keeping your muscle while losing fat will prevent metabolism slowdowns, make you look firmer, decrease body fat percentage, prevent injury, strengthen bones, and keep you independent into advanced age. For all of these compelling reasons, we strongly recommend pairing any weight loss diet with resistance training!
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Whichever diet you choose, we wish you success, and most of all, health! Pst: We're currently offering FREE membership to RP+, our online learning environment, featuring thousands of hours of health and fitness videos, hundreds of blogs, forums, and a weekly webinar Dr. Mike and Dr. James devote to answering YOUR diet and training questions.