The KETO Diet
We are surprised we didn't cover this one sooner on the podcast due to it's increasing popularity and we did frequently allude to it but here we are with a full exploration of the Keto diet. If you want to listen to Tom, Andy & I discuss the diet then listen down below for the full podcast. For a written summary continue on!
Where Did This Diet Come From?
Originally it had a medical use. Back in the early 1900s this "high fat, low carb" diet was given to those suffering from epilepsy however it's usage declined due to modern antiepileptic medicine. The classic keto diet was 90% fat, 6% protein and 4% carbs so initially, it was way more restrictive. Perhaps a reason for more people adopting this diet is due to its change in macro balance. It's now more commonly broken down into 75% fat, 15-20% protein and 5-10% carbs. So more flexibility there but still no doubting it's incredibly restrictive nature.
So we established it's initial use, but what is it mostly used for now? Weight loss seems to be the motivation of choice for this diet and of course, this is possible. The main idea behind it is your body goes into ketosis which is when you burn fat instead of carbs for fuel. Ketosis will not inherently cause you to lose weight, however. Let's take a closer look.
As we've established in previous podcasts and blog posts when you cut out a drastic amount of carbohydrates you will naturally drop A LOT of water weight initially. 1g of carb = 4g of water weight so as you can imagine cutting down your carbs heavily will have a big impact on weight. This is where we come across a lot of anecdotal evidence in those screaming from the high heavens how they lost a million pounds in the first couple weeks of keto and say keto is the best etc. Weight loss and fat loss are different.
After this initial honeymoon period without being in a consistent calorie deficit, you will stop losing weight. To lose fat you must be in a calorie deficit. The keto zealots will tell you it's all about insulin etc but that is not the case
After that initial honeymoon period unless you are in a consistent calorie deficit you will not lose any more weight. Fat loss only happens in a consistent calorie deficit. What makes a diet good for someone is if you can sustain it. The keto zealots will try and tell you that it's all about insulin and carbs are the enemy etc but this simply isn't true. Check out my post on the carnivore diet for a full segment on the facts about insulin.
We would argue that no diet is inherently superior for weight loss and if you take a controlled balanced approach to any diet you can live a healthy life.
Differences between diets are, however, generally trivial to small, implying that people can choose the diet they prefer from among many of the available diets (fig 6) without concern about the magnitude of benefits.
Ge L, Sadeghirad B, Ball GDC, da Costa BR, Hitchcock CL, Svendrovski A, Kiflen R, Quadri K, Kwon HY, Karamouzian M, Adams-Webber T, Ahmed W, Damanhoury S, Zeraatkar D, Nikolakopoulou A, Tsuyuki RT, Tian J, Yang K, Guyatt GH, Johnston BC. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials. BMJ. 2020 Apr 1;369:m696. doi: 10.1136/bmj.m696. Erratum in: BMJ. 2020 Aug 5;370:m3095. PMID: 32238384; PMCID: PMC7190064.
There are studies out there which try to say keto is superior for weight/fat loss but on closer inspection, these studies suggest that the increased weight loss is due to increased protein consumption. It's important to explore studies fully and not just read a conclusion and assume.
But we are all addicted to sugar so surely cutting out carbs will stop this and we will lose more weight! Yes, sugary foods can be highly palatable but so can high-fat foods. Evidence for sugar addiction is weak at best. Normally plenty of animal studies yet we still hear things like sugar is more addicting than cocaine etc. Go eat a tablespoon of sugar and tell me if you want to go in for another one. I doubt it. Apples also contain sugar yet people don't commonly reach for the fruit bowl for a quick sugar fix.
We find little evidence to support sugar addiction in humans, and findings from the animal literature suggest that addiction-like behaviours, such as bingeing, occur only in the context of intermittent access to sugar. These behaviours likely arise from intermittent access to sweet tasting or highly palatable foods, not the neurochemical effects of sugar.
Westwater ML, Fletcher PC, Ziauddeen H. Sugar addiction: the state of the science. Eur J Nutr. 2016 Nov;55(Suppl 2):55-69. doi: 10.1007/s00394-016-1229-6. Epub 2016 Jul 2. PMID: 27372453; PMCID: PMC5174153.
Please do not fear sugar! Everything in moderation. Of course, high consumption of sugar isn't recommended but that applies to almost anything. If you do have type 2 diabetes please consult your doctor before trying keto.
This is where things get more clear cut. In support of the keto diet or any low carb diet for that matter, we can see its beneficial application in sports that require drastic weight loss quickly such as boxing/UFC. Losing all that water weight quickly could be the difference in making weight. Let's look at actual performance though.
Heavily reducing carbs might impair performance due to our reliance on carbohydrate oxidation during endurance-based activities. There is tons of data on this! If you check out our podcast show notes you can see a list of studies in regards to this.
Once again evidence suggests that low carb intake can limit performance. However, in this short bout style type of exercise, there is data to suggest benefit and we think that's down to the lower weight held in water. Even short term we know what it's like to feel a bit sluggish after a big meal. We need more data on this.
To summarise there is no strong evidence to say that keto is superior for sports performance however we must understand that a mix of fuel types could be best for optimal performance. You may hear common comebacks such as "You didn't allow enough time to get keto-adapted it takes months!" If we actually look at the facts, all in we are looking at 2 weeks to peak in all aspects of "ketosis"
However, we also recognize that the benefits of carbohydrate as a substrate for exercise across the full range of exercise intensities via separate pathways , the better economy of carbohydrate oxidation versus fat oxidation (ATP produced per L of oxygen combusted) , and the potential CNS benefits of mouth sensing of carbohydrate  can contribute to optimal sporting performance and should not be shunned simply because of the lure of the size of body fat stores. In other words, there should not be a choice of one fuel source or the other, or ‘black versus white’, but rather a desire to integrate and individualize the various dietary factors that can contribute to optimal sports performance.
Burke LM. Re-Examining High-Fat Diets for Sports Performance: Did We Call the 'Nail in the Coffin' Too Soon? Sports Med. 2015 Nov;45 Suppl 1(Suppl 1):S33-49. doi: 10.1007/s40279-015-0393-9. PMID: 26553488; PMCID: PMC4672014.
Brain health is of course important and you normally hear statements concerning the keto diet and improved brain health. So, is this legit?
To start with glucose is usually the brain primary fuel source so you'd be forgiven in reading that and thinking so how on earth does brain not melt when we limit carb intake.
While the brain can't use fat for fuel it can use ketones. Ketones can produce 70% of the brains fuel needs. What about the other 30%? Well the other 30% is glucose and our bodies in all their glory do something called glucogeneis. This is when the liver uses protein to create glucose. Fun fact, if you have just gone over to the diet and are consuming a large amount of protein then your body may decide to use glucogeneis over ketogeneis which suggests the body does prefer glucose for energy or that it just hasn't adjusted yet. My personal opinion is that glucose is the bodies preferred energy source and that includes the brain. I'm going to continue to consume said glucose. Flip side is yes we see "memes" saying keto zealots have melting brains due to this but in fact they can make up the brains fuel requirements just fine.
To say the keto diet improves brain health is a different matter and we need a lot more data on this as up till now the bulk of this data is coming from mice/rodent studies. Not very strong data at all.
The boogy man of the dietry world. Every diet out there promises to help with cancer. What I don't like about that is it's almost a scare tactic in that people feel like they need to do diet XYZ in order to reduce risk or help with problems that arise with cancer. Truth is in regards to the keto diet there is a lot of mixed data so we need more to be more conclusive on it's effects.
A statement you may read is that cancer requires blood sugar for energy. True, but giving more sugar does not make cells grow faster and taking sugar away does not slow it down. Excess sugar of course will lead to it's own metobilic problems so we aren't condoning that!
Once again we are seeing a lot of mice/rodent studies in support of keto in it's effects on cancer. We really are lacking solid long term human studies.
This refers to a combination of issues such as diabetes, high blood pressure and obesity. These put you at increased risk of thinks like coronary heart disease, stroke and other conditions that affect the blood vessels. It's crucial we improve our health markers to reduce risk.
So, can the keto diet help with metabolic syndrome? Not inhernitly no however with proper planning and consistency of course it can. This can be said for most diets though. Normally having high levels of visceral fat comes with an increased risk of such metobolic conditions. We reduce visceral fat by going into a consistent calorie deficit but what's crucial is can we maintain this defeict and keep the fat off once it's gone. If the keto diet works for you then great! Where I think the problem lies is that with it's naturally restrictive nature and the common side effects that occur in the first week of partoiticpation (keto flu) we may see sustainability issues short/long term.
Tom made a good point on the podcast that he will sometimes do "keto" for a week to strip back water weight so he can see how much he is actually weighing without any excess water. So in that regard yeah keto may be beneficial short term but long term I really wouldn't recommend it. It's in no way superior to many other diets or just an overall balanced diet approach.
Overall we need a lot more long term data to support claims made by the keto zealots and long term data done on humans (note they have tried but these studies tend to fail). As with any diet if it works for you then great but just know this diet is nothing magical and in some cases I'd say detrimental.
Final Point. Got any comebacks to anything I've said? Please get in touch. We are all human and can make mistakes and I am in no way a fact/science deiner so please don't think I'll go full tunnel vision on any comebacks. Have you tried the keto diet or know anyone who has? Be interesting to hear how people have gotten on!
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