If you try keto, you love it, and it’s working for you, then more power to you! I’m not about to try to stop you.
However, the typical advice when people run into roadblocks with their keto diet is to ‘eat more fat to raise ketones’ and ‘keep calm and keto on’.
To understand why ‘keto’ fails for some people, it’s helpful to understand a little more about how your body uses fuel. As mentioned in Lie #5, oxidative priority is simply the order that you use the fuels available to your body (i.e. alcohol, ketones, glucose, protein and fat).
Imagine if you poured crude oil on the ground, poured petrol on top of it, and lit a match. The petrol would burn off quickly while the oil may not even ignite. Oil burns slowly, while petrol burns rapidly.
Volatile fuels like gas are hard to store. By contrast, it’s easier to store large amounts of energy as unrefined crude oil. The more we refine these fuels, the easier they are to burn. Similarly, the degree of refining and the macronutrient profile of foods you eat makes the different fuel sources behave differently in your body.
The fact that different macronutrients are harder to convert to usable energy and there are more losses in their conversion is a highly underappreciated food parameter that goes by several names, including the thermic effect of food, dietary-induced thermogenesis or the specific dynamic action of food.
Most of us do not overeat protein because it is so satiating. Your appetite for high-protein foods shuts down once you’ve had enough. It is more difficult for our body to convert protein to energy (ATP), so it is a poor source of energy for everyday use.
This means that our two remaining major fuel sources are carbs and fat. Although your body needs to maintain some glucose in your bloodstream, if you have too much, you won’t burn the fat in your blood.
Because you can only store about 5 g of glucose in your blood (about a teaspoon), a little dietary carbohydrate can quickly change your blood sugar levels (particularly if your fat stores are already full so you can’t easily absorb the excess energy from your diet).
We can convert sugar to fat (via de novo lipogenesis), but most of the time, it’s the fat in our diet that is stored because your body tries to burn off the glucose first, and any leftover dietary fat can easily be stored.
It’s not necessarily that fat is a better fuel source than carbs, but it’s the glucose that will show up in your bloodstream and register on your meter after you eat. Glucose essentially floats on top of the fat in your bloodstream and your adipose tissue.
To access your body fat, you need to deplete both the glucose and fat from your blood first.
In your body, your fuel tanks are separate but interconnected. As you deplete the glucose in your blood, it will be refilled from the glycogen stores in your liver (note: glycogen is just the fancy name for the storage form of glucose), and the glycogen stores in your muscles will be reduced. As glycogen is depleted, your body will turn to the fat in your blood, and then finally, your body fat.
You can think of your available fuels as though they are stacked up on top of each other (as shown below). So, when you measure blood glucose, you do not just measure the sugar in your blood. You really measure all the fuels stacked up in your body.
- You have very little room to store alcohol or ketones. They are more volatile than other fuel, so they have to be used first.
- Most of the protein you eat is used for muscle protein synthesis (MPS) and other critical bodily functions.
- While ‘excess protein’ not used in MPS can be converted to energy (ATP), this usually only happens when you are not eating enough carbs and fat to provide adequate energy, so your body turns to the protein in your diet or the protein on your body (i.e. muscles).
- Excess protein (i.e. that is not required for muscle repair and other bodily functions) can be excreted in the urine (i.e. it is not used for energy). A little bit of ‘labile protein’ circulates in your bloodstream, but not much.
- Protein has the highest thermic effect (i.e. 20 to 35% of energy is lost in the conversion to usable energy), so your body has to work hard to convert it to use for energy. Most of the time, we don’t usually consume ‘excess protein’ and would prefer to get energy from fat and/or carbs, so higher protein foods tend to be more satiating.
- Your body has some capacity to store glucose in the liver, blood and muscle, but not a lot compared to your body fat stores.
- If you don’t consume a lot of carbohydrates, your body will work to keep your glycogen stores topped up by converting protein to glucose (through gluconeogenesis), so you always have some available.
- You have some fatty acids in your bloodstream to use for fuel but an enormous capacity to store excess energy that you do not use.
- The amount of energy your liver drip feeds into your bloodstream from day to day is tiny compared to the amount of energy you store as fat.
- Some people can hold a tremendous amount of fat in their fatty tissue before it backs up and overflows back into their bloodstream (i.e. insulin resistance, pre-diabetes or Type 2 Diabetes).
- Meanwhile, due to genetics and other factors, other people have a much smaller ultimate capacity in their fat cells before it overflows (i.e. they develop Type 2 Diabetes even though on the outside they appear thin). This difference in fat storage capacity is known as the Personal Fat Threshold.
The bottom line is you need to deplete the upstream fuels before your body uses that unwanted fat on your butt and your belly.
To help unpack what this means in practical terms, the diagrams below show you how you can unlock each of these fuel tanks and burn your body fat. Given alcohol, ketones, and protein are not significant fuel sources for most people, we only really need to focus on glucose and fat.
The body has four main storage compartments for energy – blood glucose, liver and muscle glycogen, fatty acids in the blood and body fat. These storage containers are all separate but interconnected to a degree.
You can think of the energy flowing downhill from left to right (based on oxidative priority). If one of the downstream storage containers becomes overfull, the energy can flow back upstream due to excess pressure in the other fuel tanks.
This first diagram (above) shows glucose in your blood, glucose in your liver and muscles (stored as glycogen), fat in your blood (as fatty acids) and fat on your body as four separate tanks all connected by a ‘pipe’. You’ll notice that the pipe connecting each of the fuel tanks flows downstream towards the right. You should also note that the ‘pipe’ is not drawn at the bottom of each tank.
You don’t need to exhaust or empty each tank for the downstream fuels to be used, but rather deplete to normal healthy levels.
When you eat the standard, modern diet full of processed foods, all of these fuel tanks are full, and the ‘upstream’ fuel sources become ‘backed up’, so you never need to call on your body fat for energy.
When we eat low nutrient density, hyper-palatable foods, we continually fill our fat and glucose stores at the same time.
What’s even worse is that it is so easy to overeat these highly processed, hyper-palatable foods. We have no off switch for them when they are available, so all storage tanks get full to overflowing. This leads to energy toxicity, metabolic syndrome, Type 2 Diabetes and obesity, etc.
Let’s consider what happens to each of these fuel tanks when consuming one of three different dietary scenarios:
- low-fat/high-carb; and
- adequate protein/lower carb/lower fat.
The good news is that when we reduce carbohydrates using a low-carb or keto diet, we can start to drain our glucose stores.
However, even if you are not eating carbs, your body can always refill your blood sugar from the glycogen stores in your liver and muscles. This is why your blood sugars may continue to rise even when you haven’t eaten anything for quite a while.
Also, if the downstream fuel tanks are backed up with the fuel, you will still see high blood sugars. The blood sugar, glycogen and fatty acids in your blood will never go to zero because they will be topped up from the downstream storage tanks (via gluconeogenesis). This is why people with more body fat tend to have higher waking blood sugars.
Because your blood glucose is a small fuel tank (5 g of glucose or about 20 calories worth), it fills and empties quickly both before and after meals. It’s also straightforward to measure using a glucose metre (also known as a glucometer) to get a precise understanding of your current energy status. When we measure glucose, we are getting a good understanding of whether all the downstream fuel tanks are also overfilled.
Most of the time, waiting until blood glucose has fallen below their normal pre-meal blood sugar stops people from overfilling their upstream fuel tanks. This, in turn, causes your body to call on the liver and muscle glycogen to refill the blood glucose and usually forces people to deplete their fatty acids in their blood, which can be refilled from their body fat, and voila, fat loss from the body!
However, where some people run into trouble is when they refeed with a very high-fat, low protein diet. These foods have low satiety, so we end up eating more of them. Therefore, we consume more calories when our diet has a higher percentage of energy from fat.
In this case, the fat energy in the blood is always topped up from dietary fat, so there is never an opportunity for body fat to flow back into the bloodstream to be used. We have seen this in a number of people using Data-Driven Fasting who have very low blood sugars but are still carrying a lot of body fat. Due to a mistaken belief that fat is a ‘free fuel’ because it doesn’t raise insulin over the short term, it appears that they are continually refilling their fat tank even though their blood sugars look amazing.
When people get stuck at this point, we recommend they focus on incrementally increasing the percentage of protein in their diet (while reducing both dietary carbs and fat). This tends to improve satiety and allows both the glucose and fat fuel tanks to be drained. We’ll discuss this more in Scenario 3 – Adequate Protein/Lower-Carb/Lower-Fat, but first, let’s touch on the Low-Fat/High-Carb scenario.
In Scenario 2 (Low-Fat/High-Carb), even though blood glucose and glycogen stores are continually being filled, so long as there is only a small amount of dietary fat, blood fats will still be depleted. Hence, stored body fat will flow back into the bloodstream to be used for fuel.
While a very low-fat diet can be useful for weight loss, the reality is that very few people (unless they adhere to an ultra-strict whole food plant-based diet) can sustain a diet with low enough fat to drive fat loss over the long term. They tend to gravitate back to foods that are a mixture of carbs and fat, which allows us to consume more calories as we fill all fuel tanks at the same time. The majority of our modern processed, packaged foods are a combination of starch, sugar and fat from vegetable oil that makes refined fat hard to escape for most people.
In this scenario, we have a diet that is lower in fat and lower in carbohydrates with adequate protein. This style of diet tends to have a higher nutrient density than the other scenarios. We are satiated when we have met our nutritional requirements. Once we have obtained the nutrients we need, we are less likely to continue eating.
When we eat, we need to get sufficient protein and nutrients. You can think of carbs and fat as fuel, and we don’t need as much of it if we are already carrying a lot of unwanted body fat on our body and a build-up of glucose in our liver and blood.
As we dial back both dietary fat and dietary carbs, we deplete the carb and fat fuel tanks in our body, and our body fat can flow back into the bloodstream to be used.
Foods with a higher protein percentage and higher nutrient density tend to be very hard to overeat. So, in time, the body fat has an opportunity to flow back into our bloodstream from storage.
While you don’t have to jump to a super high-protein extreme, slowly dialling back your easily accessible energy from both carbs and fat (while still getting adequate protein and nutrients) is THE SECRET to ensuring fat loss from your body.
If we can progressively increase the percentage of protein in the diet (by reducing energy from both carbs and fat), we will tend to consume fewer calories as we drain our carb and fat fuel tanks.
To ensure you continue to make progress, I have outlined three simple steps below.
- First, dial back on refined carbs to achieve non-diabetic blood sugar variability. Your blood sugar should not rise more than 1.6 mmol/L or 30 mg/dL or after meals. This is where the ‘’magic’’ of low carb and keto happens. Many people experience greater satiety by avoiding the fat+carb combo and increasing their intake of bioavailable protein, as well as avoiding the blood sugar roller coaster. For many people, this doesn’t have to be a very low-carb, high-fat or keto diet, just enough to stabilise blood sugars. As noted earlier, very low-fat diets can also improve satiety and lead to weight loss and diabetes reversal. However, blood sugars may not stabilise as quickly.
- Next, we can use meal timing and elimination of snacks to continue the fat loss journey. Optimum meal timing is typically two or three meals a day for more active people or one or two meals for people who are less active. However, the limit here should be one ’main meal’ per day with a single ’discretionary meal’ on days you are meeting your blood sugar target.
- If you are not achieving weight loss or your waking blood sugar is not decreasing with a main meal and a discretionary meal, it’s likely that you are overfilling your diet with excessive amounts of dietary fat. You should look to increase your protein percentage, food quality and nutrient density by reducing the foods that provide more fat in your diet.
This approach is summarised in the table below.
|Step||Limit||Description||When to progress|
|1. Stabilise blood sugars||< 1.6 mmol/L or 30 mg/dL rise after meals||Reduce processed carbs to achieve healthy blood sugar stability.||When BG rise after meals is < 1.6 mmol/L or 30 mg/dL|
|2. Meal timing/intermittent fasting||One main meal with one discretionary meal (OMAD+)||Reduce the number of times you eat per day. Continue until you have one main meal with a discretionary meal that you eat based on blood sugar/weight target.||When average meals per day are less than 1.5.|
|3. Increase protein % by dialling back fat||Work up to 40-50% protein.||Slowly increase protein % (by reducing dietary fat) until weight loss re-commences.||When you have reached your target weight, body fat, waist:height or waking glucose.|
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Sample the other chapters
- Big Fat Keto Lies: Introduction
- A brief history of low carb and keto movement
- Keto Lie #1: ‘Optimal ketosis’ is a goal. More ketones are better. The lie that started the keto movement.
- Keto Lie #2: You have to be ‘in ketosis’ to burn fat
- Keto Lie #3: You should eat more fat to burn more body fat
- Keto Lie #4: Protein should be avoided due to gluconeogenesis
- Keto Lie #5: Fat is a ‘free food’ because it doesn’t elicit an insulin response
- Keto Lie #6: Food quality is not important. It’s all about reducing insulin and avoiding carbs
- Keto Lie #7: Fasting for longer is better
- Keto Lie #8: Insulin toxicity is enemy #1
- Keto Lie #9: Calories don’t count
- Keto Lie #10: Stable blood sugars will lead to fat loss
- Keto Lie #11: You should ‘eat fat to satiety’ to lose body fat
- Keto Lie #12: If in doubt, keep calm and keto on