Dear Dr. Mo: Is Keto diet good for weight loss and my health?
Dear reader: Any diet used for weight loss does so because it reduces calorie intake one way or another. The ketogenic (Keto) diet is no different there. The important questions to ask are whether this weight loss is sustainable over time and as you rightly wondered – whether it promotes long term health?
Keto diet is just the latest iteration of recently popular low-carbohydrate diets but it is special insofar as dieters are urged to avoid nearly all carbohydrates, consume high levels of fat to account for over 70% of daily calorie intake and avoid excess protein – this results in the production of ketones, hence the diet’s name.
Available data shows that keto diet is NOT clinically more effective for weight loss than other diets, when followed for at least a year or more. Ketogenic diet would result in less than a kilogram of additional weight loss over high-carbohydrate, low-fat diets. Further analysis of data shows that energy expenditure and fat loss were greater with low-fat diets.
So, mid to long-term, this diet is not superior to other diets; but, is it more beneficial for health?
No studies have evaluated this diet for cardiovascular incidents or mortality (death) but it must be said that some observational studies in the broader low-carbs/high fat diet literature suggest INCREASED all-cause mortality as reported on JAMA.
Keto diet has also been promoted to have positive effects on cardiovascular risk factors, such as serum lipid levels (fat in blood).
Again, evidence suggests that LDL (low-density lipoprotein cholesterol a.k.a Bad cholesterol) and apo-B-containing lipoprotein levels may FAIL to improve or could even INCREASE with a keto diet despite weight loss. Although HDL (high-density lipoprotein cholesterol a.k.a Good cholesterol) may increase as well, we know that various interventions attempted to increase HDL did not translate into a decrease in heart attacks and similar incidents.
Ok, so it seems that keto diet is neither superior to other diets nor good for the health. What about potential risks from being on this diet?
Risks abound unfortunately and they range from the relatively benign “keto flu”, which occurs at initiation of the diet with a period of weakness, fatigue and stomach problems to the less common but serious ones like heart arrhythmias (from selenium deficiency), kidney stones, constipation, bad breath, cramps in the muscles, bone issues/fractures, headaches, vitamin and mineral deficiencies etc.
There is one more risk or a cost if you will, not often thought of – fruits, legumes and whole grains (full of unrefined carbohydrates) are among the healthiest foods we know of – not eating them is costly for our health and long-term well being.
We know that whole grains are associated with reduction in heart disease risks, cancer risks and all-cause mortality and the same goes for fruits and legumes so there is an opportunity cost dieters invariably incur.
Ketogenic state is a risky proposition and all human populations try to eat enough carbs to avoid it. Inutis living in frigid regions of our planet have a genetic mutation to circumvent the production of ketones even though their diet consists of minimal carbs; longest living populations one finds consume diets with 50+% of daily carbs (Greeks, Japanese and similar) etc.
Of note here is that when I talk about ‘carbs’ I refer to unrefined, unprocessed complex carbs not the so called empty carbs we find in processed foods – we should not blur the line between these two very different carbohydrate groups and see them as one evil to be avoided. Cutting the good complex carbs out of our diets completely will invariably affect and degrade our health and well being mid to long term.
Now, what about some specific medical applications of the keto diet?
I am aware of the recent attention this diet has received for its promise of treating obesity and type 2 diabetes.
To my knowledge, our evidence is still insufficient to recommend keto diet as a treatment for these conditions or for anything else for that matter. As we said above, it is not better for weight loss long term and it seems that it does not do better than other dietary modifications in improving carbohydrate intolerance in type 2 diabetes.
If anything, there is evidence, as we’ve seen, of long-term harm and we should always be aware of the risks and benefits of any diet before recommending it.
As with any diet, ultimately the decision is yours but I would be cautious about jumping on the keto-bandwagon before more evidence is available to support any of its touted applications.
Canada Food Guide could be a good place to start with healthy meal planning and I wrote about glycemic index and how to use it for weight management and healthful eating. We’ll explore more on that topic in days to come.
Yours in health,