Research Review

Johnston CS et. al. Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. American Journal of Clinical Nutrition. (2006) 83: 1055-1061

Background:Low-carbohydrate diets may promote greater weight loss than does the conventional low-fat, high-carbohydrate diet

Objective:We compared weight loss and biomarker change in adults adhering to a ketogenic low-carbohydrate (KLC) diet or a nonketogenic low-carbohydrate (NLC) diet

Design:Twenty adults [body mass index (in kg/m2): 34.4 ± 1.0] were randomly assigned to the KLC (60% of energy as fat, beginning with 5% of energy as carbohydrate) or NLC (30% of energy as fat; 40% of energy as carbohydrate) diet. During the 6-wk trial, participants were sedentary, and 24-h intakes were strictly controlled

Results:Mean (±SE) weight losses (6.3 ± 0.6 and 7.2 ± 0.8 kg in KLC and NLC dieters, respectively; P = 0.324) and fat losses (3.4 and 5.5 kg in KLC and NLC dieters, respectively; P = 0.111) did not differ significantly by group after 6 wk. Blood ß-hydroxybutyrate in the KLC dieters was 3.6 times that in the NLC dieters at week 2 (P = 0.018), and LDL cholesterol was directly correlated with blood ß-hydroxybutyrate (r = 0.297, P = 0.025). Overall, insulin sensitivity and resting energy expenditure increased and serum -glutamyltransferase concentrations decreased in both diet groups during the 6-wk trial (P < 0.05). However, inflammatory risk (arachidonic acid:eicosapentaenoic acid ratios in plasma phospholipids) and perceptions of vigor were more adversely affected by the KLC than by the NLC diet

Conclusions:KLC and NLC diets were equally effective in reducing body weight and insulin resistance, but the KLC diet was associated with several adverse metabolic and emotional effects. The use of ketogenic diets for weight loss is not warranted.

My comments: Ok, so this is a study of relevance both to those that are critics of very low-carbohydrate (i.e. ketogenic) diets as well as the nutters who are convinced that they are superior from a fat loss or other standpoint. I won't get into the other issues, but want to address the ones regarding weight and fat loss. Some studies have found a greater weight and/or fat loss for ketogenic diets compared to higher carb diets.

But the problem with almost all, if not all, of these studies, is that they were relying on self-reporting of food intake. This means that people keep some type of food diary but studies show that people's ability to accurately estimate their food intake is simply horrid, and can vary from reality by up to 50%. In an interview I did for Christian Finn's website, I made that very comment. This is a problem because people are horrid at self-reporting their food intake. This makes any conclusions about diet superiority (in terms of diets at an identical caloric level) worthless. Variations in protein intake is an additional confound.

So now, finally, we get a calorie controlled study comparing a Zone type of diet (Barry Sears is actually on the author list) to a ketogenic diet over 6 weeks. With controlled calories being the key aspect. This means that the subjects had their food intake controlled for them, none of this self-reporting nonsense. And, no advantage was seen. Looking at the numbers, if anything, the 40% carb diet generated slightly higher fat loss but the difference was not statistically significant. The study also noted more difficulty on the ketogenic diet (and many people who have tried keto diets simply feel like shit all the time on them so this is not surprising).

Make no mistake, I like low-carbohydrate diets or I wouldn't have written an entire book about them. I simply don't think that they are the be-all, end-all of dieting; nor do I think they have any sort of metabolic superiority. At best, ketogenic diets seem work as well as carb-based diets in terms of fat loss. Under certain circumstances, I think that low-carbohydrates diets are more beneficial than other approaches; they can help with food control for some people (especially those who have trouble limiting their carbohydrate intake), can help with lower bodyfat mobilization and seem to be more effective (from a health standpoint) for severely insulin resistant individuals. However, in other situations, I think that moderate carb (but still sufficient protein) diets are superior. Assuming that you can control your food intake, many people simply feel better with moderate carb intakes, their training doesn't go down the shitter, and their pee and breath don't stink.

Bottom line: under controlled calorie conditions, ketogenic diet work as well, but seemingly no better than moderate carb diets. If they have any superiority under uncontrolled conditions, it's because people tend to spontaneously eat less on them. Of course, as every Atkins dieter gorging on cream cheese and pork rinds has found out the hard way, calories still count and you won't lose any fat or weight if you eat like a fucking pig all day long. Any choice of one diet over the other should be based on other issues such as compliance, lower bodyfat mobilization or health issues. Superior fat loss on the ketogenic diet isn't one of them.

As a final comment, I should probably address a potential comment that people will bring up, which is that this study might be used to argue that any low-carbohydrate diet is going to be superior to a high-carbohydrate diet. Ok, well, I'll deal with that by saying that, based on the abundant research, anybody still setting up a fat loss diet with 60%+ carbs is off their gourd anyhow. In my mind, and I don't like percentages for setting up diets in the first place, an appropriate fat loss diet should start with 25-30% protein (1+ g/lb lean body mass) and a minimum of 25% dietary fat, leaving an absolute maximum for carbs of 45-50%. Any lower protein intake and lean body mass is lost, when fat goes much below that, adherence and fullness is compromised. For all but endurance athletes (with massive caloric requirements), a typical fat loss diet start at 40-50% carbs as far as I'm concerned. Any higher carb intake and something else gets shorted. But once you get protein and dietary fat at the appropriate levels, it would seem to not matter whether you go strictly lowcarb or something more along the lines of a Zone/Isocaloric diet. As above, pick the diet based on other criterion, not fat loss; fat loss is going to be about the same regardless.

As well, I suppose someone might take issue with the fact that the subjects were obese and sedentary. Would the results be different for lean athletes or bodybuilders? Perhaps, although the feedback I've gotten over the past 15 years or so certainly doesn't support that. For some people, cyclical keto diets seem to be a little bit better but I've heard from at least as many people who get better results from moderate carb diets (and I have to wonder if the carb-load part of the CKD isn't a big part of the difference). The differences are never massive in any event. And if the pro-lowcarb folks are going to use studies on fat sedentary people to argue for a fat loss superiority of ketogenic diets, they don't get to criticize a study on fat sedentary people (that was calorie controlled) on those same grounds.

Feature Article:

Steady State Aerobics vs. Interval Training: Part

In the first part of this article (available in the archive), I defined some terms and examined various pros and cons of both interval and steady state training. In this issue, I want to look at which type of activity might be best under certain specific training circumstances (note again: the focus here is on training for fat loss).

A couple of random comments

As mentioned in Part 1, interval training hurts. It's difficult and you have to be willing to push to make them effective. Put differently, if someone is not going to work sufficiently hard at interval training, then there's really no question about intervals versus aerobics. A half-effort interval workout doesn't accomplish any of the things that interval training is trying to accomplish; if you aren't willing to push yourself on the intervals, you should simply do regular aerobic training.

And, as mentioned in part 1, thousands of people have lost fat without ever doing intervals. So while intervals may be more time efficient, and even generate more fat loss for the time invested, there's certainly no requirement to do them to get leaned out. Can they be more effective under specific conditions? Absolutely. Are they mandatory to get lean? Of course not.

Additionally, I want to point out that intervals are not a year round kind of thing, even if that's how people are using them. Endurance athletes typically only include them for intensive periods of 3-4 weeks, or occasionally for periods of up to 8 weeks. Yet somehow general fitness exercises are trying to do intervals year round. Folks shouldn't be dieting more than 6-8 weeks without a break in the first place, they sure as shit shouldn't be doing intervals for more than that without a break.

This is in addition to many people taking a good idea and being retards about it; I have heard of people performing 2 hours of intervals (20 minutes on each piece of cardio equipment) following a lower body weight workout. That's not productive training, that's exercise addiction. I've heard of people doing intervals daily (or more). Elite endurance athletes typically only perform intervals 1-2X/week, what makes you think you need more?

Finally, and I'll come back to this below, there's no fundamental reason that this has to be an either/or choice in the first place. Endurance athletes typically do 3-5 steady state aerobics sessions and 1-2 interval sessions per week, there's no reason that a dieter can't do 2 interval sessions and 2-3 aerobic sessions/week as part of their fat loss efforts. Or, depending on the specifics of their training, a maximum of 3 interval sessions and 1-2 standard aerobic sessions.

Having said that, let's look at some different population groups and how they might decide whether intervals or aerobics (or a combination of the two) might be best.

Beginners

A beginner just starting an exercise program will be best served with low to moderate intensity aerobics. They can begin to incorporate short intervals (15-30 seconds at a slightly higher intensity) after their first 4 weeks of regular training if desired. The only exception, as mentioned above would be something called aerobic interval training which is an entire separate topic.

Basically, beginners need to break in to aerobic training the way they break into any kind of training: slowly and gradually. Someone completely out of shape simply has no business working at the kinds of intensities demanded by interval training. The risk of injury is too high, the benefits too small. Even the original interval study (by Tremblay) had a 4 week break in period prior to beginning the intervals.

Once again, after 4 weeks or more of consistent aerobic training (where consistent means at least three times/week for a minimum of 20 minutes at a moderate intensity and beginners should gradually be increasing the duration of their cardio sessions as their fitness improves), beginners can begin to use interval training to continue improving fitness or increase fat loss. When intervals are first introduced, a small number of short intervals should be performed.

I would routinely have beginners start with 30-60 seconds pushing their normal cardio pace a bit and then resting for 4-4.5 minutes. This would be done throughout the entirety of their cardio session to begin introducing them to working a little bit more intensely. Over several weeks, the length of the interval would increase as the rest interval decreased.

Intermediate exercisers already involved in heavy weight training

This is where it gets more complicated because there are so many different ways that people might be training. As mentioned above, interval training is another high intensity workout and that has to be considered within the context of the overall training structure.

Local overtraining (of the legs) is a very real issue when you try to add interval training to a heavy leg training schedule. Someone who is trying to train legs twice (or more) per week and who adds intervals to that load can quickly run into problems. This applies to bodybuilders, powerlifters, and any other athlete who has to develop multiple capacities at once. There are a couple of solutions. This is why I didn't include intervals in the Ultimate Diet 2.0; it already included 3-4 lower body workouts/week. Adding intervals would have just made overtraining a near guarantee.

The first is to cut back leg training (which should really be done on a diet anyhow, I'll talk about training for fat loss in another newsletter) to reduce the overall training load. Basically, leg training should be moved to maintenance loads, with a reduction in volume, frequency, or both (intensity should never be reduced). If you were training legs for 6-8 sets twice/week you can cut back to 2-3 sets twice/week or perhaps 4 sets once/week and maintain leg strength (and size) for quite some time. Adding two days of intervals to your training, plus 1-2 regular aerobic sessions, works just fine (see comments below on sequencing). If leg training is cut back to once/week, or the volume performed more frequently is very low, intervals might be possible up to three times/week.

Athletes who need to lean out

This is another complicated situation because the term 'athlete' covers a lot of ground. Are we talking about an endurance cyclist who needs to drop some weight to be more effective on the climbs, a strength/power athlete who is cutting to make weight for a meet, a wrestler or boxer who needs to cut some fat.

The endurance athlete is probably already doing intervals and is already doing an absolute pile of long duration endurance training. Frankly, they are probably just better adding a bit more endurance work (30' of extra low intensity stuff) to their main workouts or cutting back their calories a bit.

Strength/power athletes have to worry about any non-strength work cutting into their strength and performance. Many powerlifters, for example, perform a type of interval conditioning training involving sled dragging and this is arguably more specific to their sport. A great many of these types of athletes are also carrying a lot of bodyweight (whether muscle or bodyfat) and that makes high impact activities such as running a problem. Intervals can probably be worked in 1-2 days/week along with the addition of fairly low intensity (think brisk walking) cardio another 2-3 days/week. Overtraining and performance drop should be watched for closely.

Bodybuilders

Bodybuilders dieting, either for a contest, or to prepare for the next mass gaining phase, are somewhat separate from other athletes so I'm going to discuss them separately. Bodybuilding is, fundamentally, not a performance sport. So, strictly speaking, bodybuilders (unlike a powerlifter or olympic lifter) aren't intensely concerned with poundage drops. However, dieting bodybuilders are concerned with muscle mass loss and this can be huge issue for naturals, especially if they are trying to reach contest shape. Big drops in training poundages or intensity tends to cause muscle loss when you don't have anabolics to stave it off; natural bodybuilders should be somewhat concerned of such. I would say that, contest bodybuilders, perhaps even moreso than the general public, has a tendency to overtrain on a diet. It's not uncommon for bodybuilders to increase training frequency and volume, along with adding an absolute pile of aerobic activity (2 hours/day is not uncommon), all combined with a caloric deficit. This is, of course, illogical as hell: why would you add more training during the one time period you can't adapt to it. Is it any wonder that natural bodybuilders overtrain and lose so much muscle trying to diet down?

To a great degree, I'd approach the choice of intervals versus aerobics for a bodybuilder similar to that of anybody else, even if I know most won't listen to me: they should reduce their weight training volume and/or frequency during dieting. Intensity, in terms of weight on the bar should not be reduced. Basically they should do a handful of heavy sets to maintain muscle mass; if they simply must do more work, they can do some high rep short rest work akin to the depletion workouts in the Ultimate Diet 2.0 or what's described in Alwyn Cosgrove's Afterburn program.

To this, intervals can be added two to three times/week maximum with low to moderate intensity aerobic activity being performed several more times per week.

Sequencing training

Ok, I guess I could have really summed up the above by simply saying that beginners should stick with plain old aerobics and everybody else will need to either

a. Cut back their leg training to incorporate intervals

b. Just stick with regular aerobic training

In any event, I want to talk a bit about how to sequence intervals with weight training. I'm going to assume that the person in question is training lower body twice/week, doing intervals twice per week and doing aerobics on 2-3 other days. That would at least be close to an ideal situation under most circumstances.

There are basically two ways to go about it. The first is to do the interval workouts on non-leg training days. The advantage to this is that you get to be fresher for all of the workouts, since they are all being done rested. The disadvantage is that the chances of overtraining are higher because legs are being trained intensely 4 days/week. That is, if you do interval training 2X/week and train legs 2X/week on separate days, your legs are getting hit hard 4 days/week. This can be too much.

My preferred method is to do the interval training on the same days as your leg training. Preferably the workouts would be split up (i.e. intervals in the morning, weights in the evening, or vice versa) but that isn't always possible. Intervals can be done after lower body lifting but I'd highly recommend staying away from anything that requires coordination. Trying to run sprints after heavy leg training is an excellent way to blow out your knee or turn an ankle; doing intervals before lifting just makes your lifting inefficient. You wouldn't want to exhaust yourself with interval training before weights either, another excellent way to get hurt.

So let's say we have an individual using a 4 day/week upper/lower split routine who wants to do 2 days of intervals and 2 days of aerobic training. Here's how I would suggest sequencing it.

Mon AM: intervals PM: lower body weights

Tue: AM: aerobics PM: upper body weights

Wed: Off (brisk walking would be allowed for active recovery)

Thu: AM: intervals PM: lower body weights

Fri: AM: aerobic PM: upper body weights

Sat: Off (brisk walking would be allowed for active recovery)

Sun: Completely off (everyone should take at least one day off per week).

Questions and Answers

Q: Hi. I have a problem with the information given in the "Rapid Fat Loss" book vs the "Crash Diet Forum" on-line.

The book is recommending almost unlimited amounts of fibrous vegetables. In an answer in the Forum you are referring to an amount of "a few vegetables" in the diet. Since there is a lot of yelling in the Forum about "read the book" this is a bit confusing. I'm totally aware of the starchy carbs, that's not the problem, the amount of vegetables is.

A lot of low calorie vegetables (cucumber, Romain leafs, celery, peppers etc.) can end up to quite a sum of carbs - some advice in the form of grams/oz or % of total calories would simplify the diet, at least for us using a diet computer program with exact calculated amounts of everything.

A: Unless you are just eating kilos of the stuff daily, I don't see how the caloric content of most fibrous veggies is worth worrying about. Even if it does add 100-150 calories/day (unlikely IMO), you've still got a massive deficit going on and fat/weight loss should be relatively uncompromised.

Q: I'm a 19 year old female who is 5'2" and weighs about 85 pounds, I don't know my body fat percentage, but despite not being overweight, I think it is high since I can grab a lump of skin from my stomach. I don't have access to devices to measure body fat or any expertise in their use if I were to obtain them(calipers), who can I consult for advice with this and what would be a good method for someone of my size to lower body fat

A: You can get body composition measured in a variety of ways at a variety of places. A lot of gyms use bioelectrical impedance, mainly because they are easy and require no training. Unfortunately, they are not very accurate unless you stick to strict hydration protocol. Calipers are the most accurate (relative to ease) but you have to know what you're doing with them and a lot of trainers do not. More expensive methods like underwater weighing, BodPod or DEXA are expensive and probably not worth the investment.

However, it's just as good to keep track of waist size (with a tape measure), bodyweight and strength in the gym. This gives you a very rough (but reasonably accurate) measure of what's going on. If you're losing inches and weight is either the same or going down, you're losing fat. If your strength in the gym is staying stable, you're generally not losing muscle. Boom, you know exactly what's going on.

As far as lowering bodyfat, you would approach it just like anyone else (although at 85 lbs, I would question how much fat you really need to lose): a combination of weight training (2-3X/week), moderate amounts of cardio (3-4X/week for 30-40 minutes) and watching your diet. There's no magic, the main ingredients are smart/hard work and patience.

Q: What's a deload?

Deloading refers to a period (usually a week) where the volume, intensity and/or frequency of training is reduced to allow fatigue from the previous weeks of training (typically three but this isn't set in stone) to dissipate. There are many ways to perform a deload but most will reduce volume (total sets and reps) by up to 50%, frequency may be reduced and intensity (weight on the bar) is often reduced to about 80% of the previous week's loads. A typical training schedule might be 3 weeks of progressively heavier training (pushing for personal records in the third week) followed by a 1 week deload.

After longer periods of training (2-4X4 week training cycles), a longer deload (often used as a taper) of up to 3 weeks may be followed to peak performance.