Ketogenic Dieting Hype – Separating Fact from Fiction – Part 3

Who Would Benefit from a Ketogenic Diet? (this is part 3 in the series. To start at the beginning click here)

Keto diet hype

In my opinion a ketogenic diet would suit the following people:

  1. People who want to lose weight but find it difficult to stick to a calorie deficit with a carb-inclusive diet*
  2. Obese or near-obese people who struggle with blood sugar peaks/crashes and feel sluggish after carbohydrate consumption*
  3. Those who are purely interested in losing weight and not sport or exercise performance*^
  4. People recovering/rehabbing from Type II diabetes, provided a doctor has done full blood work to assess their body’s competence at dealing with certain fats with respect to lipoproteins and general cholesterol sensitivities.

*note that these issues could probably also be fixed with a diet that is more selective when it comes to carbohydrate choices

^the third point there is a contentious one for me because of the lack of exercise. Weight loss itself can be a medical emergency, and I understand cases where people are so morbidly overweight that exercise is not really a viable option until some mass has been lost.

BUT the vast majority of people who are considered obese, near obese, or those who simply don’t dig the thought of training (but still want to lose weight) usually diet for the simple goal of watching the number drop on the scales.

I’ll say this until I’m dead: weight loss, by definition, includes lean mass, especially muscle mass, unless you do something to preserve it. What good is getting lighter if you also become weaker?

High Protein Diets

People often tout high protein diets as a means to avoid ditching muscle mass, but it’s only partially helpful because you are still in an overall calorie deficit in order to lose weight.

That means you are spending more energy than you are consuming and if you lead a sedentary lifestyle on top of it, that energy deficit will start to manifest as fatigue.

Of course, the argument to that is: you still have to be in a calorie deficit to lose weight even if you are working out, so surely you will be even more fatigued.

My response to the arguments in favour of sedentary ketogenic dieting – actually any calorie deficit diet with a lack of exercise – is this:

If you diet without exercise you are still not conditioning your body to digest, process, allocate and store the macronutrients – or indeed the micronutrients – you consume, at anywhere near optimal efficiency OR efficacy.

Exercise, particularly a blend of resistance training and cardio-vascular training will not only optimize your body’s use of nutritional intake but will improve so many other facets of your health, including emotional well-being, immunity and general energy levels.

Man and woman keto dieting

Improve Your Physique

Not only that but it will improve your physique and give you purpose to the dieting in the first place. Often people lose weight but don’t see much of an aesthetic difference in their physique. This is due to weight being lost evenly over the body at a slower rate than visual perception allows.

By meeting the weight loss with training-induced body compositional changes the transformation is much more dramatic and far more likely to engender the desire to continue.

Not only that, but physical training will shorten the time it takes to reach your goal bodyweight and therefore the time it takes before you can start consuming maintenance calories rather than a calorie deficit – and that’s an achievement.

So, taking all of that into consideration, the avoidance of carbohydrates becomes less and less important as you increase activity level.

Keto or no keto, exercise will accelerate your progress, and depending on the intensity level of your training, being in ketosis may actually start to inhibit your fitness gains.

woman resistance training and keto

Ketogenic Dieting combined with Resistance Training

There are people extolling the supposed muscle-preserving benefits of ketones and the notion that strength, muscle and fitness gains while following a ketogenic diet can be comparable to those made while following a carb-inclusive diet.

To me and many others, it’s impossible.

Ketones simply cannot supply the same energy requirements that glucose, glycogen and thus carbohydrates can when exercise intensity increases and oxygen demands can no longer be met.

This is because ketones can only be converted back to Acetyl-CoA, which then donates its acetyl group to the citric acid cycle. The citric acid cycle being that which is fed by beta-oxidation of fat and/or oxygen mediated (aerobic) gylcolysis (of glucose).

As exercise intensity increases and oxygen demands cannot be met, a greater energy load obviously shifts to anaerobic respiration. Glucose is the only source of fuel which can be converted to ATP via lactate in an oxygen independent environment.

For someone in ketosis to meet such energy requirements, sources other than carbohydrates must be converted into glucose via the process of gluconeogenesis.

The tax on the system corresponds to a lower energy payoff when compared to the relative efficiency of glycolysis involving dietary carbohydrates.

Furthermore, as I’ve already discussed, gluconeogenesis is neither a quick process nor one which will supply fuel indefinitely.

Converting protein or glycerol to sugars to facilitate high intensity exercise is akin to robbing Peter to pay Paul from a biochemical standpoint, and the human body just won’t allow it to happen for long.

To put this issue to bed, it would be great if a series of scientific experiments focused on direct comparisons of athletes following a ketogenic diet, a moderate carb-inclusive diet and a high-carb diet.

A mixture of men and women, both trained and untrained would be excellent.

A nice year long study would be fantastic, and if they could somehow blind the subjects to the diets they were on that would be perfect.

Of course, this isn’t going to happen anytime soon, and so we must rely on the data we do get.

Recently, one such study was published comparing the efficacy of ketogenic diet on body composition during resistance training in trained men.

resistance training with Keto men

Hypercaloric Condition

The plan for the study was to have the subjects in a hypercaloric condition, i.e. a calorie surplus.

I’ll let you delve into the study I’ve linked to above if you want the specific design parameters etc. but one thing the scientists didn’t do too well was monitor the diet adherence.

As a result, the ketogenic group appeared to have experienced an unintentional calorie deficit, given they lose both fat mass and lean body mass (LBM).

The non-keto group on the other hand experienced a small drop in fat mass, but a significant increase in muscle mass.

Had the keto group maintained a calorie surplus the results would have been much more interesting, but they are nonetheless quite compelling.

Perhaps the most interesting outcome is that the ketogenic diet group, despite aiming for a moderate calorie surplus, lost weight.

This can be interpreted in two ways:

Ketogenic diets have an appetite/hunger suppressing effect and are therefore effective for weight loss
Ketogenic diets are not conducive to hypercaloric conditions and therefore not suited to people looking increase muscle mass.

The appetite suppressing effects of high fat diets are well documented and it comes as no surprise that this was the cause of the weight loss in the study, in spite of equated protein intakes and resistance training program.

What is surprising is that the scientists running the study simply stated in their conclusion that the keto group experienced no significant changes in lean body mass “despite hyperenergetic condition and high protein intake”.

The hyperenergetic condition refers to the calorie surplus. So the scientists themselves don’t point this out as a condition which can’t have been met, considering the (albeit non-significant) loss of fat mass and LBM.

This sort of conclusion might leave people wondering what magical effect keto diets have to cause fat loss even in hypercaloric conditions.

Instead, what should be focused upon is the obvious fact that the keto diet caused an unintentional calorie deficit.

Perhaps most telling result that is the carb-inclusive group (or non-keto group) lost a non-significant amount of fat mass but gained a significant amount of LBM.

Given they were training and eating high quantities of protein, this makes perfect sense.

In the end, this study was really a comparison of a calorie surplus carb-inclusive group and a calorie-deficit keto-group so you’re more than within your rights to throw it out as completely flawed. Hopefully, however, you can still see the value in it, regardless of its misgivings.

Mildly amusing to me is that the ketogenic group couldn’t eat a calorie surplus even when they intended to. That in itself puts a big dent in the whole “keto doesn’t compromise muscle gain” argument, in my humble opinion.

When you pair that with the race walker study from earlier, keto doesn’t seem ideal for endurance training either.

Should the keto athletes in the resistance training study have forced themselves to attain a calorie surplus, the results would have been very interesting.

Personally, I believe their lack of available glucose/glycogen for maximal output would have still hindered their potential for gains in lean body mass, but until a study is carried out that can investigate that in hypercaloric conditions we cannot know for sure.

About Ross T. 78 Articles

Ross T., CPD Certified in sports nutrition, BEng
I've probably forgotten more about training, nutrition and supplements than most people ever learn. Why? Because I've never stopped learning. These are dynamic fields of expertise that are constantly evolving, and qualifications mean nothing if you don't consistently update your knowledge base. You can also read more About Me.

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