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4 Sep 2012

Ketosis & how it works

This post is in response to some questions I've been asked down through the years about Ketogenic dieting and "Ketosis".  It's a wordy post, and won't be of huge interest to everyone, but perhaps it might prove interesting to some!

Now, I am not one of those "eat to live" people; I wish that I were, but I just love eating.  So from time to time I have Dabbled with Diets.  I have ridden that Weight Watchers pony.  I had a brief period of madness when I used Celebrity Slim Shakes (gross disgusting overly-sweet absolute muck that does nothing for you).  I subscribed to Dr Eades Protein Power Plan (highly recommended).  I have Done Detox.  The Zone and I were buddies for a while, and I even looked into Eating For Your Blood Type .  I followed whatsisname's JuiceMaster programme.  I subscribed to yucky Chinese herbs (that you boil on Sunday, allow to cool, and drink all week - gag).  All during this time I have been reading, researching, absorbing, talking to nutritionists, dieticians, doctors, you name it, and I have eventually come to my own brand of dieting/healthy eating/whatever you want to call it.

Essentially, it follows the high-protein-low-carb "Paleo" approach favoured by Dr Eades, Atkins, "Pig To Twig" and a bunch of other programmes.

It works.  But it needs discipline.  But frankly, any "diet" or "healthy eating plan" will only succeed with preparation (remember the 7 Ps*) and discipline, determination, self-belief, actualisation, a long-term attitude and lot of other stuff that seems insurmountable at the start of any programme, and becomes easier as you go along.

Proper Planning and Practice Prevents Piss Poor Performance

Sadly
Necessary Disclaimer
Before advancing, I should caveat this with a disclaimer.  This information is all factually true and based on my own experience.  I stand behind my understanding of it all but I am by no means an expert.  This post is intended as information, not advice.  Any dietary or eating plan should not be undertaken lightly, and with consideration of your own weight, health and possibly in consultation with your own doctor or nutritionist.


Food, glorious food!

Ok, a preamble about the obvious stuff.  There are essentially three different food types, carbohydrates ("carbs"), protein and fat.

Carbohydrates
("carbs")
  • Carbs contain four calories per gram
  • There are two basic types of carbohydrates (both contain the same calories/gram): Simple & Complex
  • Simple carbohydrates are high in refined sugar, which contains 'empty' calories (i.e. essentially non-nutritious);  too much refined sugar tends to disrupt our appetite mechanism and can cause food cravings
  • Complex carbohydrates are no lower in calories but take longer to digest, keeping us fuller for longer and helping to keep blood sugar-levels (and appetite) stable

Fats
  • Fat gives you about nine calories per gram
  • For a maintenance diet, you should restrict the calories from fat to about 20% of your total intake

Proteins
  • Protein contain four calories per gram
  • It is better in general to monitor your intake of high-calorie animal protein
  • Protein is used for building, maintaining and repairing muscle, skin, blood, and other tissues (note that fuel (or energy) usually takes precedence in the body over this tissue building/repairing activity).
  • When the calorific supply from carbs and fats is adequate, very little ingested protein is used as fuel.  But if carbohydrates are not adequate, protein can convert to carbohydrates via gluconeogenesis.


In the normal course of events, the body uses two fuels for energy; fat and glucose (glucose = blood sugar).  Carbohydrates in the diet first break down in the body as glucose.  When you cut back on carbs, you leave only one source of energy (fat).  However fat is an inefficient fuel source, the body has to work extra hard to convert it to energy (which, in ketosis, is a double plus for the dieter).

Very simplistically, ingested carbs are partially used up for fuel and partially stored;  ingested proteins are "fuel burning" nutrients.

When in a state of ketosis, excess protein and fat in the digestive system is converted into blood glucose in a process called gluconeogenesis and then distributed into various cells of the body via insulin, or passed through the urine.  So while we definitely need to eat both fat and protein, we don't essentially need to ingest carbs.  That's the first thing you need to know.  Carbs are not evil, and green fibrous vegetables in particular are great for you, but technically we don't need them.


So what is ketosis, exactly

Ketosis is a mode of bodily operation in which you force your body to use its fat stores as fuel.  That's it.  It can only occur if you deplete your body of carbs.

Ingested carbs are used up for fuel in a complicated way, which depends on your body's glycogen stores and insulin levels.  The more carbs you eat that you don't burn (which will depend on your lifestyle and your body's basic metabolic rate), the more that will get stored as fat (as any food not needed by your body for energy is converted to stored body fat), then the higher your insulin levels become, then the less likely that fat will be used for fuel... and so on, a vicious cycle.  

You can break this cycle with a ketogenic diet.  In such a diet, you only ingest proteins and small amounts of fats - no carbs - and in this way, trigger the body to burn up fuel (stored fat).

KetonesKetones are the by-product of this process of ketosis - the stored fat that is burned off, or metabolised, turns into ketones (simplistically, three different ketones) in your body, and these ketones are then used as your body's energy source, instead of the ingested carbs (as you're not eating any carbs to be used as an energy source).

In order to enter this state of ketosis, the glycogen in your liver must be emptied (ingested carbohydrates are stored in the liver as glycogen, as well as in the muscles.  When the liver is depleted of glycogen, a state of ketosis is achieved.  For the dieter, it's interesting to note that glycogen acts essentially like a sponge, so for every one pound weight of glycogen in your body, you can have three-four pounds weight of water stored with it).

It's not uncommon for a healthy adult to naturally shift into partial ketosis (overnight in particular for example).  But you can prolong this ketogenic state by avoiding carbs altogether for a period of time, in order to burn stored fat very quickly and efficiently.

So ketosis essentially makes fat storage metabolically impossible, as body fat is being utilised as fuel.


Digressing for a minute - how many kCal do you need each day?

To find out how many kCal you need, first multiply your body weight (in lbs) by 14.
     e.g. for someone who weighs 12stone:
    12 stone * 14lbs * 14 (factor) = 2,352 kCal max needed each day for "normal" function.

So, say this person wants to gradually lose approximately 2lb per week (using a "standard" or non-ketogenic diet/eating plan), he needs to create a calorie deficit of about 7,000 kCal in that week.  Running the sums, this amounts to a max kCal intake per day of no more than 1,352kCal a week to lose this weight (which can be done through diet, or exercise, or a combination thereof).  This will obviously need to change (lower) each week as he loses weight and needs to adjust to ingesting less calories in order to achieve this 2lb loss a week.


Low-carb, No carb and VLCDs

During a low-carb diet, as some carbs are ingested, this doesn't allow for full ketosis, you may enter ketosis during the night, but in general there may not be enough carbs or total calories ingested to maintain adequate energy levels, leading to a certain degree of fat burning, but not a lot.  You may also feel lethargic on a low-carb diet, as your body isn't taking in enough fuel (from ingested carbs), and not burning enough fat to turn into fuel either.  It is not unusual to have low insulin levels, constant hunger, muscle loss... on a diet like this.


Dropping the carbohydrate count to zero-carb and raising the fat calories slightly will allow the body to enter ketosis and use ketones as fuel.  While in ketosis, it's usual to feel energised and energetic, no lethargy here, as your body is producing all the fuel it needs.  Using ketones as fuel also regulates insulin levels throughout the day, which can also help with energy levels.  Diets like this are very often recommended for people who need to monitor glucose or insulin levels.  On such a diet, you usually have high amounts of energy, feelings of well-being, rarely will you feel hungry (protein tends to make you feel full and satisfied), you'll have a high level of fat burning and minimal muscle loss.


In general, the "average" adult needs about 2,000 kCal a day to haul their ass around, and approximately 800kCal a day to maintain a normal core body temperature.  This is why VLC, or Very Low Calorie ketogenic diets work - if you drop below this 800 kCal per day, your body needs to work very hard to maintain your core temperature and also cart you around, so you lose weight quite quickly.  That said, there have been many studies that suggest there's very little difference in the weight lost between people ingesting less than 800 kCal a day, and people ingesting around 800kCal a day (while on a ketogenic diet).

This is the great misconception surrounding VLCDs, the reason they have such a bad name is because many don't understand ketogenic dieting and therefore are not comparing like-with-like;  when you're in ketosis - and in particular if you have a lot of fat stores that can be turned into fuel - you need less calorie intake in order for your body to function efficiently and for those fat stores to be adequately burned as fuel.  So you can get away with ingesting much less calories providing they are protein and fat only and you're in ketosis.

I'm not advocating VLCDs, I'm simply explaining how/why they work if you're in ketosis and doing them properly.  When you're doing a standard (non-ketogenic) diet, (ie one that contains carbs), you're not in ketosis, your body isn't naturally in fat-burning mode, and your fat stores and incoming carbs both are used in a complicated way as previously intimated.  VLCDs are dangerous, if you're not in ketosis.  If you're in ketosis and have a lot of weight to lose, they are actually perfectly safe (once you stay no more than 500kCal below maintenance intake).


How do I reach, and maintain ketosis?

I have been asked over and over how to achieve and maintain ketosis, when following a paleo-type/protein-based/zero-carb diet.  It's simple.  If you want to reach, and maintain, a ketogenic state, then you need to completely skip the following:
  • Carbs.  All of them.  That does mean all.  No vegetables, salads, fruits, rice, pasta, bread, sugars or starches.  None.
  • All alcohol
  • Anything with citric or acetic acid (lemons, limes, citrus fruits etc, vinegars, diet drinks, soluble vitamin c or soluble analgesics etc...)
  • Salt
  • Dairy products (for some reason cheese and natural yoghurt doesn't affect some people, but milk usually does)


Surprising, isn't it.  You can have herbs but not fruits.  So you could have herbal teas but not fruit teas (lemon verbena leaf tea = good, lemon tea = bad, for example!)  In terms of condiments, pepper and dried chilli, herbs etc are fine, but skip the salt.  And forget about those soluble analgesics and multi-vitamin drinks too, as these usually contain citric acid which can kill ketosis.

It takes three-six days for your body to divest your body of its glycogen (ie its "instant energy source").  Every time you cheat (and eat some carbs) you start back at scratch again.  If you're serious about this, you really do have to stick to no-carbs.  I won't pretend it's pleasant for those first few days, at least until your body (and in particular your brain) adjusts to using ketones and not glucose as its primary fuel source, but after this initial three-six days you'll feel immensely better, in fact you'll feel better than you have for some time.

Your body will shed its glycogen at a rate of knots for the first week, so weight loss is generally just glycogen and water loss during this time.  After that, the actual fat-burning weight loss starts (your body starts metabolising stored fat to use as fuel), so the longer you can stay in ketosis, the more you will lose in a short space of time.  If you genuinely want to get into ketosis, then you need to commit to at least a month of this kind of dietary plan, as otherwise all you're doing is losing glycogen and excess water, not actual stored fat.


After that month, I generally would recommend a return to a gradual phase-in of carbs, over a one-two week period.  Start with greens;  salads and green vegetables in particular, raw or slightly cooked (green fibrous vegetables can't be converted to energy like normal carbs, so don't "count" as ingested carbs and will help you stay in at least partial ketosis.  Leave out the fruit, root (or other starchy) vegetables, avocados, tomatoes (these are rich in simple carbs (as described above - ie sugars)).  Remember: the more carbs you introduce, especially starchier ones, the less likely you're still in ketosis.  And this is where the fat burning magic happens.

Funky breathWhen you are deep in ketosis, and your body is burning up a lot of fat, using some and excreting some, you can have metallic tasting breath and funny smelling pee.  Nice!

Remember that I said there are essentially three different ketone bodies produced as a side-effect of ketosis?  Well, it's the acetone ketones that are being excreted as waste causing this smell).

This is not a bad thing per se, it's just a sign that your body is burning up stored fat, producing ketones, some of which are not used as fuel but instead become waste and excreted through usual waste-disposal functions (skin, breath, liver/kidneys etc).


So what can you eat?
  • Eggs are one of the most complete foods out there.  Eat them fried, poached, boiled or scrambled (if scrambled, use no milk).  The myth that they contribute to cholesterol is just that, a myth (perpetrated essentially by the larger cereal companies in the 60's, to further cereal sales for breakfast - sounds a little conspiracy theorist, but true!)
  • Meat/fish - cold meat, fried, poached, grilled, broiled, roasted, grilled, bbq'd, whatever.  Just avoid marinading/serving in sauces.  And ditch the processed meats as these often contain cereals (carbs), salts (kill ketosis), nitrites (just plan bad for you).  Processed meats include cold cuts, salami, rashers (bacon), sausages, white/black pudding (blood pudding) etc.
  • Cheese is allowed in small amounts.
  • If you're a vegetarian, this diet is a little harder for you.  Nuts of course are high in protein and saturated fats, but generally contain a high proportion of carbs too.  Soybeans are great but high in oestrogen, so be careful with them.  Legumes and beans are ok but generally are high in lectins, and you need to seriously watch your intake of those as they can be highly toxic.
  • Bovril, Marmite, miso (as long as not made with rice) those kind of things are usually low-fat, low-calorie, high-protein, low-carb, not bad.


Fats are your friend

Cooking proteins in fat is not a problem when you're on zero-carbs; protein and fat can be metabolised together by your body when in ketosis (your body can't metabolise fat plus carbohydrate, which is why potato chips are such a no-no, as anything that can't be metabolised and "used" by your body as fuel is automatically just "stored", ie turned into fat).

Obviously use discretion, deep-frying your steak is still not good for you (not to mention disgusting). Stick to olive oil if you can, and use small amounts of oils.

Fats are very important for the production of hormones in your body, so it's quite critical that you don't eat just protein and no fat.


Water, water everywhere, and not a drop to drink

Probably the single most important thing in any diet/eating plan is water intake.

Water is so important.  Essentially, the rule of thumb is that you should be drinking about one litre of water a day per 32kg of weight you're hauling around.  Aim for slightly more if you're trying to maintain ketosis, as your kidneys are working extra hard when you're doing a ketogenic diet, and water helps keep them flushed out.  In addition, when you are in ketosis, your body is producing ketone by-products as waste that can taint your breath with a metallic taste, as mentioned before.  Drinking water helps with this.  Just be careful;  too much water will cause an electrolyte imbalance, never a good thing.  I aim to drink four litres a day, and never allow myself to go under three.  And I feel great; upping your water intake alone will always make you feel truly energised and energetic!

In addition, if you're trying to curb appetite, drinking water helps, as it will help you feel sated.  It's worth noting that our brains don't have the ability to differentiate between hunger and thirst, so quite frequently when we think we're hungry, we are actually thirsty.  The feeling of thirst is in fact an early warning signal for dehydration, not thirst.  So by the time you feel thirsty, you're technically generally already dehydrated, to some extent or other.

Drinking with meals?  Nope.  But drinking a glass of water about a half hour before each meal is a good habit to get into.  It's best not to drink water with (or immediately after) your meal if you can avoid it, as it skews digestion.


"Diet" Drinks & Foods

Give these a large skip!  Low-fat or slim-line drinks and "foodstuffs" can contain chemical alternatives to sugar which can (a) be linked to cancer (b) crash your blood sugar levels and cause headaches, hunger and lack of proper digestion of ingested food.  Not all "sugar equivalents" are evil, some are essentially fibre-based, but in general most of the chemical sugar alternatives are genuine muck.


Some rules that I (try to) live by
  • Carbs and fats can't be digested together: so eat them separately.  This is the main rule to follow, irrespective of ketogenic dieting or otherwise.
  • Your body can metabolise protein and carbs together to a point: but it's better if they're eaten separately (this principle is what the Zone diet is based on).
  • Proteins and fats can be digested and metabolised together: so it's ok to have these together - but as always, in moderation and with portion control in mind.
  • Don't eat after 7pm if possible to allow your body to digest all that you've ingested over the day.
  • Don't drink after 8pm if possible (unless you want to pee all night long!)
  • Carbs are better eaten in the earlier part of the day - if you can, avoid eat carbs after lunch.

Don't think for a half a second that I'm this uber-disciplined, controlled person.  I am not.  I go through phases, and I am at times more successful than at other times!  But as a number of people have asked me about ketosis, I thought I'd just write a blog about my experiences and my own research over the last ten years.

Feel free to ignore all of this, and please note that the information given here is based on my reading, research and empirical evidence (as applied to me).  As previously stated, I am not a doctor, I am not a nutritionist, I just know what works for me and the science behind why it works.

Ketogenic diets can seem a little Too Good To Be True.  They can seem a bit like magic.  A lot of people don't grasp how the body functions when in ketosis, hence the lack of understanding.  But I personally guarantee you will feel so much better if you give one a go, either as a weight-loss tool, or for a carb-detox once every so often.

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