The Best And Worst Diet Plans

- Muscle Insider Special Report -

Paleo, Zone, Atkins, low carb, keto, IIFYM … which diet should you be following to maximize muscle gains while improving body-fat losses?

You may have the heard the refrain “You are what you eat,” and that’s true nowhere more than in bodybuilding. While it’s pretty obvious the super-sized McDeal isn’t going to be packing on pounds in all the right places, it’s a mistake to think nutrition science can be boiled down to an easy-to-follow formula or list of foods.

In fact, any number of eating plans (we’ll call them diets) can help you achieve your physique goals. Some are good, others more are suspect. Among those best suited for individuals whose aim is to improve their physique, we’ve narrowed the list to the top seven contenders. Although you may be inclined to ask which one is best, let’s be clear: You won’t know until you try them. That’s because, quite simply, no single diet works best for everyone. Quite likely, if you gave the same diet to five different people, you’d get five different outcomes! What’s more, if your goals change, that too can affect your success.

In consideration of the above, the best way to discover your best diet is to look at each of the popular diet programs below that physique athletes follow and their potential advantages and disadvantages, including their effects on performance, muscle growth and recovery, fat loss, and health. Included in this overview are these heavyweights: very low-carb ketogenic (Atkins), low carb (including carb cycling, South Beach, Zone, etc.) high protein, fasting, Paleo, IIFYM, and the Mediterranean diet.

1. Ketogenic Diet

Over the last decade or more, no nutrient has been in the spotlight more than carbs when it comes to performance, gaining muscle, and especially losing fat. Bodybuilders back in the 1960s often cut their carbs to get lean, and then low-carb dieting hit the mainstream with Dr. Robert Atkins’ book, Dr. Atkins’ Diet Revolution in the early ‘70s. By the turn of the century, almost 10 percent of North Americans were on the diet. If you’re a bit of a geek, check out some YouTube videos by the world’s leading keto expert, Dr. Jeff Volek. I remember meeting him at a science conference about 20 years ago and being influenced by his research on this type of diet, and he’s been studying it ever since!

A ketogenic (keto) diet is one that’s low enough in carbs to cause your body to produce ketones, which, in the absence of adequate carbs, are required as fuel by the brain for it to continue to function. So basically, when your carb intake gets so low that you aren’t delivering enough glucose to the brain, your body produces ketones as an alternative energy source. Because there are no carbs available in this circumstance, the rest of the body is forced to increasingly use a higher percentage of fat for fuel. To achieve this, we’re not just talking about reducing carbs by a few percent; carb intake has to come way down to about 50 grams per day, or less!

One of the obvious limitations with “keto” is that over-restricting carbs reduces performance during intense exercise because the body uses a progressively higher proportion of carbs over fat for fuel as intensity increases. This is because fat cannot be as quickly metabolized as carbohydrates to produce energy. Because ketogenic diets force the body to use primarily fat for fuel and can’t deliver carbohydrates (glucose) as quickly, this limits performance in intense activities such as higher-rep or short-rest-between-sets weight training and activities such as sprinting and the like that require more than a few seconds of maximal or near-maximal effort.

Performance in lower-rep lifting, especially with longer rest periods between sets, shouldn’t be significantly affected in most people, especially after the dieter becomes accustomed to being in ketosis (which takes two to six weeks). It has been suggested, and some research (much of it conducted by Dr. Volek and colleagues) supports the notion, that once adapted to a ketogenic diet, performance will improve, and some endurance and extreme-endurance athletes seem to have success with keto diets. But most coaches and experts still believe that the performance advantage lies with higher carb diets. Certainly when it comes to intense (anaerobic) exercise, performance is impaired on keto diets, so total training volume and/or intensity will be affected and therefore so will be performance improvements.

This performance deficit appears likely to be a drawback when it comes to building muscle because you’re unable to complete as many reps in a set or to do as many total sets at a given weight. This is especially true for those who respond better to higher-rep, higher-volume training. For those who respond well to training in the lower-rep ranges, keto may not impair gains. In fact, it’s important to point out that some ketogenic diet studies have shown both better fat loss and better muscular gains simultaneously than with a more normal carb intake. However, more research is required because in the key study on this topic, the ketogenic subjects consumed more protein.

Unlike performance and muscle, there’s strong evidence that keto can deliver the goods for weight loss. Initially, the numbers on the scale drop dramatically. Suddenly, severe carb restriction means the body rapidly loses most of its stores of carbohydrate in the muscle (called glycogen). Because each gram of this stored carbohydrate carries 4 grams of water, when it’s lost, a large amount of weight is lost rapidly. This has in fact been a major criticismof this diet. Still, it doesn’t mean that people aren’t also losing fat, and indeed the Atkins diet does seem to cause fat loss as effectively or more effectively than many other diets. Additionally, some people become highly motivated because of the dramatic, initial weight loss! It should be noted, though, that because keto diets also usually mean greater protein intake and less totalcalorie intake (because of lower hunger and restricted food options), it’s probably mostly these effects, rather than something magical about being in ketosis per se, that are behind the diet’s success.

On further problem for fat loss on this diet is that you can’t achieve the same high degree of intensity in the gym; much recent research suggests that protocols such as higher-intensity interval training (HIIT) are more effective for fat loss.

You can’t discuss keto/Atkins without discussing its effects on health. “Experts” have warned of the dangers of this diet’s high fat—and particularly its high saturated fat content—for years. For me, that isn’t the issue because markers of cholesterol and metabolism are similar or even superior for the Atkins diet, if you choose your foods intelligently. The original Dr. Atkins’ Diet Revolution focused mainly on upping fat greatly and ditching the carbs without much of a focus on other nutrients. Not ideal! However, Dr. Atkins’ New Diet Revolutionincludes several revisions such as focusing on healthy vegetables and healthy fats. This makes it a nutritious diet and probably superior for diabetics and those with poor insulin function.

So keto may work well for someendurance athletes but not very well if you take your intensity up to or near 100 percent for prolonged durations or frequencies. Also, unless you thrive on low-volume, low-rep workouts with long rests between sets, it’s not ideal for maximizingmuscle endurance or likely muscle growth. As for absolute strength gains, most of the best strong men still do higher rep work in addition to their sets of five or fewer, and higher rep work can be an effective contributor to absolute strength. So overall, this diet probably isn’t ideal for most guys trying to get bigger and stronger in the gym. When it comes to weight loss, the diet works well but probably not better than other diets that are high in protein. When it comes to health, if it’s followed strictly and includes enough vegetables, fibre, and healthy fats, the Atkins diet is as good or better than the standard low-fat/high-carb choices and works best in those with poor insulin function.

2. Low-Carb Diets

Now that we’ve gone through most of the technicalities of what happens when you cut carbs severely and when you eat more protein, I can be briefer in explaining the merits and weaknesses of the other diets. By “low carb,” I mean any diet that decreases carb intake. The difference between this and keto diets is that you will rarely, if ever, take carbs low enough for long enough to go into ketosis.

When it comes to performance and many other considerations, the low-carb diet has most —probably all—of the benefits of the keto diet without most of the drawbacks. A typical-sized man can still perform intense anaerobic exercise by eating 200 or fewer grams per day. This means that he could take his daily calories down to 2,500 and carbs would make up only a third or less of his calorie intake. Also, by consuming your biggest carb meals in the three- to six-hour window before intense training, you can have the benefits of lower carb intake and still maintain the same, or very similar performance.

When it comes to muscle growth, because low-carb diets still accrue all of the anabolic benefits of insulin and most guys who eat this way and go to the gym also eat high protein, there’s no negative effect of lower-carb diets on muscle growth and recovery.

Ideally, someone using a low-carb diet will either already be consuming high amounts of protein (ideally at least 2 grams per kilo of body weight, or roughly a gram per pound of body weight daily) and will just cut the excess carbs out or they’ll gradually replace some of the carbs in their diet with protein. Either of these strategies will cause effective weight loss. Diets with a higher ratio of protein to carbs have been shown in dozens of studies to significantly outperform high-carb diets when it comes to fat loss, according to new research. The lower carb intake reduces hungerand the higher protein intake reduces hungerand preserves metabolically active muscle tissue.

Carb cyclingis a form of low-carb dieting in which you have lower- and higher-carb days and/or you have (as suggested above) more carbs strategically before your most intense workouts. This can work very well by strategically providing a level of carb intake that’s appropriate for the level of energy output you intend to expend in the near future.

So low-carb diets have most or all of the advantages of keto without the disadvantages: lowered performance, feelings of fatigue, and not being well for the first few weeks. They also don’t impose the severe restrictions on your food choices, which can make keto diets a difficult long-term commitment. Again, you have to figure out how your particular body handles carbs and adjust accordingly until you find the ideal dosage.

3. High-Protein Diets

Protein is ideal for making you feel full longer, increasing metabolic rate, requiring more energy to metabolize, and helping to maintain muscle during a calorie-restricted phase. Anyone who desires more muscle, less hunger, and less body fat should be on a higher-protein diet.

To implement a high-protein diet without excess calorie intake, either fat and/or carbs must be replaced with protein. The vast majority of studies have looked at diets that replaced carbs with protein and kept fat the same. Both will probably work well, but because of the essential nature of dietary fat and the many types of fat that should be included in the diet in ideal ratios, it’s nota good idea to decrease fat intake beyond a certain point. Therefore, when we talk about effective and research-proven high-protein diets, we’re essentially talking about the lower-carb diet as discussed above, with all of the same performance, muscle, fat loss, and health benefits.

4. Fasting

The jury is still out on fasting. I’ve seen research showing that it may help with the aging process, other studies say it could impair gains in muscle, but I’ve also read research that it can work well. It certainly seems to work by the obvious mechanism of decreasing overall weekly calorie intake. Performance-wise, I wouldn’t want to try to do any significant amounts of intense exercise after a day of fasting, but most people can time their exercise around their one to three weekly fasting days. Theoretically, fasting should lead to some muscle loss, but in the long term, if the diet is otherwise intelligently practiced, the body probably somewhat compensates for these long durations without food if you’re trying to build muscle (although research is lacking).

For fat loss, again, fasting will work, but I’d think that having three or four very low-calorie meals consisting of just protein or protein and non-starchy vegetables would arguably burn even more fat and reduce the chances of losing muscle. Of course, fasting can mean only eating within a four- to eight-hour window each day, or it can mean not eating for 24 hours one or more times per week, and no one is yet sure if one or both of these methods are useful.

5. Mediterranean Diet

This brings us to the Mediterranean diet, the darling of mainstream nutritionists and dieticians today. Again, as with my comments on fasting, yes, the Mediterranean diet out performs a typical diet for health, but what diet wouldn’t when you see the stuff most North Americans are typically eating? Recently, one of the key studies that supports the effects of this diet was called into question and had to be retracted, so it has lost some of its credibility of late. Overall, this diet is great because of its focus on fish, vegetable, fruit, and healthy fat intake, but for the purposes of Muscle Insiderreaders, it can be improved by a reduction in excess starchy carbs and the addition of more protein, which would make it just as healthy but with the advantages of the high-protein, lower-carb diet discussed previously.

6. Paleo

This diet focuses on the consumption of foods eaten throughout most of the evolution of our species, meaning unprocessed, nutrient-dense foods that are high in protein and low in sugar and starch. That makes it consistent with the low-carb, high-protein diets we’ve already discussed. I’d advise adding whey protein and calcium (for both performance, muscle, fat loss, and health), but otherwise it’s an excellent way to eat to achieve all of the goals that are the focus of this article.

7. If It Fits Your Macros (IIFYM)

This isn’t actually a diet but a necessary, basic consideration of anygood diet. All diets should be constructed with macronutrient ratios in mind. IIFYM can work for any of the goals we are trying to achieve here, but remember aside from macros you must eat enough fibre, vitamins and minerals, phytochemicals (healthy plant chemicals), and effective, performance-enhancing supplements. That doesn’t make IIFYM a diet in itself but rather the basic framework of your diet.

What It All Means

Most North Americans mistakenly follow a high-carb diet, and you’d guess correctly that I’m not a huge fan. It contains unnecessarily high levels of carbs, which for most people means eating too much starch and sugar, which can result in constant hunger, poor insulin function, weight gain, tiredness, and inadequate protein intake. Except for some endurance athletes (and this is being challenged more and more these days), it has noadvantages in any of the measures considered in this article.

So in a nutshell, keto diets are unnecessarily low in carbs and high-carb diets contain them in excess, with no proven advantages compared to more moderate intakes but with several drawbacks. Many of the advantages of keto diets result from decreased calorie intake and higher protein intake, and the disadvantages of high-carb diets is greater hunger and the fact that all those carbs usually come at the expense of lower protein intake. The Mediterranean diet has never been tested against a healthy low-carb diet and if it were, a healthy, higher-protein, lower-carb diet would almost certainly lead to more fat loss and less muscle loss. The very occurrence of greater fat loss with this diet would probably also lead to better health outcomes. Fasting may work for some and has potential (but it has yet to be adequately studied). Paleo basically is a high-protein, lower (but healthy) carb diet, and IIFYM isn’t a diet at all but one key aspect of setting up your diet.

Ultimately, the optimal diet is one with a high protein content with a carb content that fits your personal carb sensitivity and is gradually adjusted in line with your performance and aesthetic goals.