Having examined the moderate-carb/moderate fat diet in Comparing the Diets: Part 3, I now want to turn my attention to one of the more contentious dietary approaches out there: low-carbohydrate/high-fat diets. I’ll also provide an end-of-article chart showing how the different dietary approaches may be more or less useful in a given situation.
A quick note on the percentage nutrient notation: as much as possible I tried to adhere to a format where the percentages represent percentages from protein/carbohydrates/fat in that order. So a notation of 30/60/10 means a diet where 30% of the calories are protein, 60% are carbs and 10% are fat.
And finally we come to the low-carbohydrate or ketogenic diet, the diet with perhaps the greatest amount of controversy and argument surrounding it. Now, at the risk of beating a dead horse, and since I find many of my critics to be a little slow on the uptake, I’m going to go off on one last rant about this topic.
Rant mode on:
If you think of me as the keto-guru, you’re probably expecting me to advocate the ketogenic/low-carb diet over all the others. People seem to think since my first book The Ketogenic Diet was about nothing but, I must be the diet’s strongest promoter. It makes me wonder if these morons actually read the book since I made it clear there that I didn’t feel that ketogenic diets were necessarliy ideal. I repeated this multiple times within that book. People didn’t get it.
I’ve actually found two different criticisms of my attitude towards ketogenic diets, depending on whether the critic is pro- or anti-ketogenic diets.
First is the group that feels that, since I didn’t write negatively about keto-diets, I must be their biggest advocate. Since they dislike ketogenic diets on some level, they feel that I should as well. Anyone who writes honestly and fairly about them is, by definition, in favor of them. This is moronic by the way.
The second groups seems to feel that since I didn’t say that ketogenic diets are magic, I must not believe in them. Since they think the diet is magic, they think I should too.
Both groups, as usual, are guilty of projecting their own personal biases onto me. Both groups are apparently unable to count beyond two, since they see the world in a rather simplistic ‘for/against’ way.
To make things clear to both groups, I’m going to sum up my attitude towards ketogenic diets one more time. I’ll be using simple words as much as possible.
My opinion on ketogenic diets is this: ketogenic diets are one of many (ok, three) dietary approaches available. They have advantages and disadvantages (like all diets). They are appropriate under some circumstances, relatively neutral under others, and entirely inappropriate under still other circumstances. They are not magic but they work tremendously well for some people and absolutely horribly for other. There are still questions regarding their long-term effects.
Of course, you could make the same statement about any dietary approach as I’ve discussed throughout this series. They all have pros and cons, advantages and disadvantages. But since keto diets are among the most contentious, and since my name is essentially equated with the ketogenic diet, I’m having to make my stance that much more clear.
The point I’m trying to make, and one that I will continue to make (probably for the rest of my life since morons will always think of me as the keto-guru), is that, it’s a matter of context, always. Whether a given diet, or training program, or supplement or drug is ‘the best’ always depends on context.
And if you continue to think that I only advocate or believe in ketogenic diets after reading that, I strongly suggest you go get your head checked for signs of trauma because you would seem to have a rather large comprehension problem.
Rant mode off
Now, I want to point out again, while a ketogenic diet is a low-carbohydrate diets, not all low-carbohydrate diets are ketogenic diets. As detailed in the article How Many Carbohydrates Do You Need, an intake of carbs below 100 g/day is required to induce ketosis to any measurable degree (most ketogenic authors set an initial daily limit of 30 grams/day but I’ve never found a rationale for this recommendation). Not all low-carb diets reduce carbohydrates below the 100 g/day level so not all will induce ketosis. However, for the sake of typing and reading simplicity, I’m going to refer to all diets in this section as ketogenic (again, by definition containing 100 grams carbohdyrate or less per day).
For the purposes of this section, and as mentioned in Comparing the Diets Part 1 I’m going to set carbs at 20% or less of total intake for a low-carbohydrate diet. Protein will be set at 30% (and possibly higher) and the remainder of the diet will be fat (in this example, 50%). As carbs go lower, fat intake goes higher, of course, up to the limit of 0% carbs and 70% fat. I should also mention that some authors prefer to do low-carbohydrate diets as nearly all protein affairs, with little to no dietary fat. My own Rapid Fat Loss Handbook takes this very approach but it also sets out to generate a massive daily deficit.
I should probably mention that ketogenic diets actually come in a few varieties. First are the standard or strict ketogenic diets (SKD) where carbohydrates are kept reduced for extended (or unlimited) periods. Most of the mainstream low-carb/keto diets fall into this category.
Second are the modified ketogenic diets which come in two flavors. The first is diets which reduce carbohydrates throughout the day but allow small amounts of carbs before, during, and/or after training. We named those targeted ketogenic diets (TKD) in my book The Ketogenic Diet and I’ll stick with that name. Finally are the cyclical ketogenic diets (CKD) such as Bodyopus, The Anabolic Diet, and Rob Faigan’s NHE diet which alternates periods of ketogenic dieting with phases of high-carb intakes. Since all of these diets revolve around a ketogenic/low-carbohydrate phase, I’ll discuss them together.
Let’s look at the SKDs first and when and where they might be appropriate. Frankly, I could probably just tell you that, if you don’t meet the requirements for either of the previous two diets, some type of ketogenic diet is going to be appropriate for you; it’s a choice by exclusion. To be safe, I’ll include a little more commentary than that.
Obviously, folks who aren’t doing much (or any) activity, ketogenic diets tend to be appropriate. Now, it’s easy to simply say ‘You should exercise and eat more carbs’ but this isn’t always possible. In cases of extreme obesity, or injury, or just plain laziness, exercise (especially intense exercise) may be out of the question. Since carbohydrate requirements are going to be extremely low (approaching the minimums discussed in How Many Carbohydrates Do You Need?), a ketogenic diet can be appropriate under those conditions.
Even individuals doing nothing but low-intensity activity (think walking and such), carbohydrate requirements are rarely very high. Low-carbohydrate diets are also appropriate under those conditions. There is some evidence that a low-carb diet might be useful for ultraendurance athletes (who typically perform for hours on end at fairly low intensities) but the data is mixed and the issue contentious; at some point I’ll write a full article (or book) about that topic alone. I’ll talk about higher intensity exercise performance in a second.
I’ve also found that folks with extreme insulin resistance do better in terms of energy levels and hunger/appetite control when they reduce carbohydrates, as I discuss in Insulin Sensitivity and Fat Loss, fat loss may be greater as well. They go from constant energy swings to more stable energy. Research typically report rather significant improvements in many health parameters such as blood cholesterol and triglyceride levels although this depends on total caloric intake and fat source as well. But for those individuals with severe insulin resistance and the resultant hyperinsulinemia (high-insulin levels), a near complete reduction of carbs may be necessary to bring glucose and insulin levels under control.
Along those lines, some people simply feel better on low-carbohydrate (especially ketogenic diets). They feel mentally more aware and function better, especially after a few weeks of adaptation. At the same time, some folks never seem to adapt to such diets, always feeling brain fuzzed, lethargic and all the rest. Many folks couldn’t care either way. Is this genetics, a micronutrient imbalance, individual variance? I have no idea, but I’ve seen it enough times to know it happens.
My general experience, in terms of giving you some guidelines to go on is this: if you feel fine, meaning that you function well with no major energy swings on a carb-based diet, odds are you’ll feel horrible on a ketogenic diet. You probably have good insulin sensitivity, high levels of activity, are fairly lean and are genetically well suited to run on carbohydrates. Don’t mess with it.
If you’re one of those individuals who always feels lagged out and un-energetic on high-carbohydrate diets (or get major energy crashes after a high-carb meal), you’ll probably tend to feel wonderful on a low-carbohydrate diet. You may be inactive, carrying too much fat, or simply be genetically insulin resistant, meaning your body isn’t set up to handle lots of carbohydrates.
This is where individual variance starts to play a role. I suspect that the differences in response have to do with many of the factors described in the previous sections: activity, insulin sensitivity and the rest. At the same time, research is finding that some people seem to be better adapted to using fat for fuel while others do not (meaning their bodies prefer carbohydrates).
Genetics most certainly plays a role. Unfortunately, at present there’s no easy way to know who will do best with higher fat and who won’t. Use the guidelines above: if you feel good on high-carbs, you’ll probably feel terrible on low-carbs and vice versa. Some people seem to have the metabolic flexibilty to handle either approach at which point it’s more an issue of preference and the other related issues.
While I feel that a moderate carbohydrate/moderate fat diet will probably be sufficient for all but the most extreme cases, there are always those individuals for whom a nearly complete reduction in carbohydrate intake may be necessary.
And, as above, for those folks for whom even moderate amounts of carbs make them hungry for more carbohydrates (this tends to be far more true for starches than anything else), a complete removal of them may be necessary at least for the time being. I’ve found that, after time on a ketogenic diet, most people lose their taste for the high GI starches as their taste buds adapt. Frequently they can go back to a more moderate carb/moderate fat approach without getting into problems.
This is actually an important point, even for athletic individuals. Even with the most stalwart dietary discipline, athletes can have problems reducing calories on a diet because of the presence of what we might call ‘diet-breaker’ foods. That is, even in small amounts, certain foods make people cheat and overeat. While dietary fat can be problematic here, starches and sugars are typically what’s craved on a diet.
Now, as anyone who read my rather torturous Bodyopus diaries so long ago knows, I am (well, used to be) one of those individuals. Even the smallest taste of starch made me want to eat more. Keeping bread or what have you in the house meant a diet that was destined to fail. Over time, I’ve found balance, I can (and usually do) use a moderate-carb/moderate-fat diet without running into too many problems.
As well, even athletic individuals can suffer from some degree of insulin resistance (at a genetic level) and may not handle carbohydrates well. In Bodyopus, Dan wrote that he felt most bodybuilding failures were do to poor insulin sensitivity. While I think it would be more clear to say that it’s due to poor nutrient sensitivity and uptake, the general idea is still sound. This is discussed in more detail in the articles on Calorie Partitioning.
For those individuals, even who are highly athletic, a complete removal of the diet breaker foods (or foods that interact negatively with genetically poor insulin sensitivity) may be a necessary evil. As above, while I think moderate carb/moderate fat diets will probably do most of the work this isn’t always the case. Some people will have to remove those foods entirely from their diet to be able to stick with it.
As well as I’ve mentioned throughout this article series, stubborn fat (ab/low-back fat for men and hip-thigh fat for women) comes off better when carbs are restricted. The Stubborn Fat Solution details the along with how to utilize low-carbohydrate intakes and specific training protocols to target stubborn fat.
So now we have a contradiction, even highly active individuals (meaning high carbohydrate requirements) may find a situation where carbohydrates need to be restricted to very low levels. The question then becomes of how to sustain exercise performance on such restricted carbohydrate intakes.
Most critics of ketogenic diets would simply say ‘Eat more carbs’ but, as above, this may not be an option (also, as above, these people are idiots who can’t see past a single dietary approach). So we have to compromise. Modified ketogenic diets are that compromise: they let folks use ketogenic diets while trying to maintain performance with the inclusion of carbs at specific times.
To date, two primary solutions have been developed, both of which I mentioned above. The first, and perhaps the simplest is the Targeted Ketogenic Diet (TKD). The TKD allows varying amounts (usually 25-50 grams) of high GI carbohydrates before, during or after training with carbohydrates being severely restricted the rest of the day. This accomplishes a few things. First, it allows dieters to eat some of the diet breaker foods, but under controlled circumstances. This helps deal with some of the psychological issues involved with dieting. Second, it goes a long way towards sustaining exercise performance by providing carbs around training. Third, since insulin resistance isn’t much of a problem right around training, the high GI stuff that everybody likes to eat can be eaten fairly ‘safely’ (from a blood glucose/insulin release point of view).
Even extremely insulin resistant/pre-diabetic individuals can usually eat carbs right after an intense workout without problems, as exercise elevates insulin sensitivity to high levels temporarily (there is also insulin indepdendent glucose uptake during exercise so the body can utilize glucose without having to increase insulin levels).
The second solution, and the one I suspect most readers are aware of is the cyclical ketogenic diet (CKD). A CKD refers to any diet which alternates periods of low-carbohydrate (or ketogenic eating) with periods of high-carbohydrate eating. Diets such as DiPasquale’s Anabolic Diet and Metabolic Diet, Dan’s Bodyopus, and Faigan’s NHE are all examples of CKD’s. My own Ultimate Diet 2.0, of course, represents the pinnacle of cyclical diets of this sort.
CKD’s are another compromise diet approach: they switch between a ketogenic/low-carbohydrate phase (for anywhere from 5 or more days) and a high-carb phase (lasting from 12 to 48 hours or more) to restore muscle glycogen and hopefully generate an anabolic response. They are for those athletic individuals who, for one reason or another, needs to restrict carbohydrates severely, but sustain exercise performance.
Active individuals with severe (diagnosed) insulin resistance or even the beginning of Type II diabetes tend to fare poorly on CKDs; the extended carb-load period causes all of the problems that they are trying to avoid in the first place. The TKD is more appropriate for them.
On that note, I should mention a seemingly contradictory situation, that of endurance athletes. Interest in fat loading and fat adapting endurance athletes has been a long-term project for exercise physiologists and some research suggests that some endurance athletes can benefit from following a low-carbohydrate/high-fat diet for some period of time (5-21 days) and improve performance (more recent research suggests that it kills sprint performance even within the context of a long-duration event).
This is especially true for ultra-endurance athletes who may perform for many hours at submaximal intensities, relying predominantly on fat for energy. A recent series of studies found that fat adapting cyclists for 5 days followed by a 1 day carb-load (similar to a CKD) improved performance in some athletes. The fat adaptation increased fat utilization at lower intensities but the carb-load made sure that sufficient glycogen was available for high intensity efforts. Again, this is a topic deserving it’s own full article or book so I won’t get into many details here.
Summing Up Low-Carb Diets
So summing up the section on low-carbohydrate diets. As above, we have two basic flavors of low-carb diet. The first is simply a diet in which carbohydrates are restricted for extended periods of time. Such diets are appropriate (and may be desired) for individuals who aren’t doing much, if any, exercise (or are only doing low-intensity activity), who may have severe problems with insulin resistance, who have such an extreme carbohydrate ‘addiction’ that a full removal of starches may be required to control hunger.
The second flavor, the modified low-carbohydrate diets come in two separate groups. They are for those individuals who need (for some reason) to lower carbohydrates to low levels but still need to sustain exercise performance. First are the targeted type diets which have dieters restrict carbohydrates except around exercise (this is actually a very common approach to diet setup in bodybuilding literature). Second are the cyclical diets that alternate some period of low-carbohydrate dieting with periods of high-carbohydrate intake to refill muscle glycogen (and sometimes, it’s argued, to stimulate a growth response).
Finally, the Chart You’ve Been Waiting For
Ok, now you’ve hopefully got a better idea of which diet approach may be the most ideal for you. To make it a little more clear, I’m going to try to summarize all of the above information into a chart so you can see how the different variables interact.
|Diet||Activity Level||Insulin Sensitivity||Carb Choices||Carb Addict||Stubborn Fat|
|Mod carb/mod-fat||Medium||Low-moderate||Medium GI||Maybe||Yes/Maybe|