Can MCTs skirt the need for strict keto?

Part I.  Ketones are made from fat in the liver.  But dietary fat has a lot of places to go and people to see, so it rarely gets to the liver en masse to a degree great enough to stimulate ketosis.  Not so much for medium chain triglycerides (MCTs).  Upon entry (ingestion), MCTs go to the liver and are metabolized to ketones without passing GO or collecting $200… but is this sufficient to reap the benefits of a ketogenic diet?


MCTs (C8-10) comprise ~14 of the fat in coconut oil, and 9.2% in dairy.  As such, average MCT intake is low – ~2% of total fat intake [because we eat a lot of vegetable oil and not a lot of coconuts].

Exhibit A.  Weight-loss diet that includes consumption of medium-chain triacylglycerol oil leads to a greater rate of weight and fat mass loss than does olive oil (St-Onge and Bosarge, 2008)

Healthy people assigned to either ~21grams of either MCTs or olive oil (~12% of total calories on a hypocaloric 1650 kcal/d weight loss diet) for 16 weeks:

This.St Onge BW

and this was accompanied by a healthy reduction in body fat:St Onge fat mass

Since ketones weren’t reported in this study, we have no way of knowing if they were even involved, but these data look very similar to those found in Partsalaki’s obese children put on a low calorie vs. ketogenic diet (Partsalaki et al., 2012):Partsalaki BW

and Hussain’s type II diabetics on low calorie vs. ketogenic (Hussain et al., 2012):Hussain BW

Thus far, data from the St-Onge’s MCT study look similar to two ketogenic diet studies (Partsalaki & Hussain).  But ketones weren’t reported in any of these studies, so it’s hard to know if they were involved.


Exhibit B. Stimulation of mild, sustained ketonemia by medium-chain triacylglycerols in healthy humans: Estimated potential contribution to brain energy metabolism (Courchesne-Loyer et al., 2012)

Brain needs glucose.  Or ketones.  Elderly brains use 10-15% less glucose than young brains, and Alzheimer brains use 20-25% less.  Thus, ketones stand to provide great benefit.

Healthy young adults given ~30 grams MCTs (C8-12) for 4 weeks.  Plasma ketones tripled.  3X.  This isn’t a ketogenic diet or starvation, where ketones increase 5-10 fold, but a normal diet with added MCTs… a major difference between the two is insulin levels: they didn’t budge in this study because carb consumption remained intact.  We’re trying to “cheat” the ketogenic diet, remember?Courchesne-Loyer

St-Onge’s MCT oil study used 21 grams of MCTs which was accompanied by profound weight loss.  Courchesne-Loyer showed that 30 grams can induce a pretty healthy state of ketosis.  Do you think St-Onge’s subjects were ketotic?  I do, especially because they were losing weight.

From our furry little friends,

MCTs increase HSL (Liu et al., 2011) & NE (Liu et al., 2012) in adipose from mice fed relatively low doses of MCTs (~2% [w/w]).  Norepinephrine has a curious relationship with keto’s anti-epileptic activity, as mice lacking NET (read: increased noradrenergic signalling) still benefit from keto (Martillotti et al., 2006)… However, NE ko mice don’t (?) (Szot et al., 2001).

My guess is that a diet supplemented with MCTs or coconut oil will not be superior to bona fide keto, but could be a very effective adjunct to enhance traditional low carb.

Why not?            MCTs lack that certain umph, or chutzpah, associated with ketogenic dieting

MCTs vs. regular CTs (from Bosch et al., 2011):Bosch

Yes, these MCT-fed mice were eating less despite burning just as much, so they gained less body fat, but it was nothing like Garbow’s ketogenic mice who were eating way more yet still weighed less (Garbow et al., 2011):Garbow

Man cannot live on MCTs alone… but he’d probably do pretty well on low carb plus MCTs.

calories proper

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  • Pat Davitt

    In the Garbow study, what do you think it was that caused the ketogenic mice to gain less weight while eating more food?

    • William Lagakos

      Hi Pat,

      Thanks for the comment.

      I think its primarily energy expenditure, with a possible minor contribution of calorie absorption/excretion. I wrote about the Garbow paper in Episodes II & III of the Ketosis series:

      Were you thinking something different?


      • Pat Davitt

        Nope. Just as I suspected. Thanks for clarifying though.

      • Dana Seilhan

        Of course, there is more to energy expenditure than mere exercise. And when it comes to exercise, something has to be said for *available* energy. I have heard a lot from low-carbers and Paleo eaters who improved their diets and suddenly *wanted* to move around more. Lack of motivation for exercise is a frequently cited reason for weight-loss failure. Maybe all these weight-loss goo-roos are just looking in the wrong place.

        • William Lagakos

          Hi Dana,
          Thanks for the comment. Yeah, I usually say “energy expenditure” as a blanket phrase to include REE, BMR, PA, etc., when I don’t have the time or space to dissect the components.
          And I’m totally not surprised that improved diet and/or weight loss precedes increased motivation for exercise – cool observation though.
          all best,

  • Dr Dea Roberts

    Thanks for this. Only small quibble is that I’m not sure about puttig it like this: dietary fat “rarely gets to the liver en masse to a degree great enough to stimulate ketosis”. I have never heard that it is a flood of fats arriving at the liver that determines ketone production. ?
    I do appreciate your article anyway and, as I said, that is a small detail. If ony perfect posts could be posted, I wouldn’t dare post a thing.

    • William Lagakos

      Hi Dea,
      Thanks for the comment and insight. When I wrote that I was thinking regular dietary fat compared to MCTs, both of which in the setting of low carb. In that scenario, I think a flood of MCTs would definitely promote at least a transient ketosis… but a bacon cheeseburger with a cola wouldn’t – which is probably what I should have written.

      ‘only perfect posts’ :)

      all best,

  • Lifextension

    Ooh, fascinating post!

    • William Lagakos


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  • Jesse

    What about a keto diet with MCT oils like coconut oil?

    • William Lagakos

      Yes, exactly: My thinking is that MCTs and coconut oil should allow you to eat more protein or carbohydrates and still maintain a respectable level of ketosis. It’s speculative, and shouldn’t be used long-term, but if your goal is “ketosis,” then they might be useful supps.

  • William Lagakos

    Medium-chain Triglyceride Ketogenic Diet, An Effective Treatment for Drug-resistant Epilepsy and A Comparison with Other Ketogenic Diets

    The ketogenic diet (KD) is one of the most effective therapies for drug-resistant epilepsy. The efficacy of the medium-chain triglyceride KD (MCTKD) is as excellent as the classic KD (CKD), which has been documented in several subsequent retrospective, prospective, & randomized studies. MCT oil is more ketogenic than long-chain triglycerides. Therefore, the MCTKD allows more carbohydrate and protein food, which makes the diet more palatable than the CKD. The MCTKD is not based on diet ratios as is the CKD, but uses a percentage of calories from MCT oil to create ketones. There has also been literature which documents the GI side effects from the MCTKD, such as diarrhea, vomiting, bloating, & cramps. Therefore, the MCTKD has been an underutilized diet therapy for intractable epilepsy among children.The author has used up to >70% MCTKD diet to maximize seizure control with GI side effects optimally controlled. As long as health care professionals carefully manage MCTKD, many more patients with epilepsy who are not appropriate for CKD or modified Atkins will benefit from this treatment. A comparison between the MCTKD and other KDs is also discussed.

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  • George

    Here’s a canine n=1, my dog started having seizures (a cluster of 3 every 2 weeks on average) at the start of the year, like my neighbours’ dogs on either side of us. She was (unlike them) eating a meat based diet, so I increased the fat and decreased protein to try to make it a keto diet. End result, she gained weight, seizures didn’t really change. I’ve started giving her coconut oil. And this really seems to help, without increasing her weight, indeed her appetite seems reduced. She’s also started eating small amounts of fried and frozen vegetables (okra, broad beans, molokhai, blueberries, and grated coconut) lately on her own initiative. She seems much better already (two and a half weeks without a seizure). I give her a couple of teaspoons of coconut oil 2-3x daily.

    • Bill Lagakos


      I’d bet that, given their more carnivore-biased metabolism, dogs are resistant to ketosis even on a very high fat diet. Maybe this is why it took coconut oil to push ketones high enough to have an effect. Cool.

      • George

        She’s getting up to three weeks without a seizure now, and a very convincing sign that it’s working is that her general health is improving – her cognition and intelligence and mood is what it was before the seizures, and she has less and less twitching and metabolic distress (panting for no reason).
        Today when I took her for a walk she started chasing cars again. I never thought I’d be happy to see her do that.

        • Bill Lagakos

          MCT/keto diet for canine epilepsy:

          Despite appropriate antiepileptic drug treatment, approximately
          one-third of humans and dogs with epilepsy continue experiencing
          seizures, emphasising the importance for new treatment strategies to
          improve the quality of life of people or dogs with epilepsy. A 6-month
          prospective, randomised, double-blinded, placebo-controlled cross-over
          dietary trial was designed to compare a ketogenic
          medium-chain TAG diet (MCTD) with a standardised placebo diet in
          chronically antiepileptic drug-treated dogs with idiopathic epilepsy.
          Dogs were fed either MCTD or placebo diet for 3 months followed by a
          subsequent respective switch of diet for a further 3 months. Seizure
          frequency, clinical and laboratory data were collected and evaluated for
          twenty-one dogs completing the study. Seizure frequency was
          significantly lower when dogs were fed the MCTD (2·31/month,
          0-9·89/month) in comparison with the placebo diet (2·67/month,
          0·33-22·92/month, P=0·020); three dogs achieved seizure freedom, seven
          additional dogs had ?50 % reduction in seizure frequency, five had an
          overall <50 % reduction in seizures (38·87 %, 35·68-43·27 %) and six
          showed no response. Seizure day frequency were also significantly lower
          when dogs were fed the MCTD (1·63/month, 0-7·58/month) in comparison
          with the placebo diet (1·69/month, 0·33-13·82/month, P=0·022).
          Consumption of the MCTD also resulted in significant elevation of blood
          ?-hydroxybutyrate concentrations in comparison with placebo diet (0·041
          (sd 0·004) v. 0·031 (sd 0·016) mmol/l, P=0·028). There were no
          significant changes in serum concentrations of glucose (P=0·903),
          phenobarbital (P=0·422), potassium bromide (P=0·404) and weight
          (P=0·300) between diet groups. In conclusion, the data show
          antiepileptic properties associated with ketogenic diets and provide evidence for the efficacy of the MCTD used in this study as a therapeutic option for epilepsy treatment.

          • George

            Thanks Bill!
            Bluebelle had 3 fits at the 3 week mark. These were pretty short and there was an improved recovery in that she wasn’t depressed during the 3 days or so that it takes, recently she’s been depressed for weeks but this time her activity and interaction with us was more or less normal soon after the fits. She gets shaky and a bit uncoordinated for a few days. But still, looking better so I am hoping for more improvement in the long term. Wonder if she’d like MCT oil…

          • Bill Lagakos

            “Wonder if she’d like MCT oil…”

            dunno, but it’s pretty cheap and if she doesn’t like it, you can still cook with it (I think)