"Life Without Bread"

[dugdeep]

In "The Ketogenic Diet," by Lyle McDonald, he says it takes 3 weeks for the body to adapt to ketosis. During that time, your muscles will be using a lot of ketones trying to spare all available glucose for the brain. I gather this is when people can be feeling side effects like exhaustion, headaches, etc. probably because the body is running inefficiently, muscle using ketones when it's used to using glucose, but should really be using fat.

Once the conversion happens, which seems to be signaled by the brain switching over to using ketones, all the parts of the body that can run on fat (muscles, organs, etc.) stop using ketones and start burning fat. Ketones get shuttled to the brain, which starts running on them almost exclusively (as much as 75%). This is probably when you start feeling like a million bucks :D

I'm not sure, but I think if you "cheat" or screw up during that initial 3 week period, you may be back to square one (this is just my speculation, not from the book). Also, I don't think it requires going to super-low carb, or zero-carb, to make the conversion. It just requires patience and dilligence (again, my speculation).

 

[SeekinTruth]

I'm a little bit confused about the vitamin C intake.
I've bought Vitamin C (ascorbic acid) and it is recommended to only use 120mg per day ?
but I think I've read that some of you take much more ?
how much should I take per day ?

Maybe this article by Robert F. Cathcart, M.D. will help you understand better. He helps you find your vitamin C tolerance level.

There is also a topic on the forum: Ascorbic acid

fwiw

When you find your bowel tolerance, you take the Vitamin C close to that amount, which will fluctuate. For example, when you're healthy, let's say you'd have found you should take about 5000 mg per day. If you get sick it will go up, so you keep increasing when you're sick until just before bowel tolerance is reached (gas, bloating, gurgling starts, but before diarrhea starts).

If you're going through a mild illness, your tolerance may go up to, for example, 8,000 or 10,000 mg per day. If you've got a more severe illness, it may go up MUCH higher before reaching bowel tolerance (it can get into tens of thousands mg / day.)

 

[Gaby]

Here is a quote from "The Art and Science of Low Carbohydrate Living" to see which fuel our organs prefer to use as an energy source. The key is to have fatty meats in order to have an energy intake of around 70% coming from fat. If you increase the energy intake from proteins alone (lean meats), and not fats, it will not be the same and you might actually get sick.

What Your Organs Burn

Here's a question for you - do all cells and organs in your body use the same fuels? Specifically; if your diet consists of 20% protein, 30% fat, and 50% carbs, do all cells throughout the body use this identical fuel mix? The answer, of course, is "no" (because if it were "yes", why would we be asking this question?)

Some cells prefer fats for fuel, others prefer glucose, and some are so specialized that they prefer just one particular amino acid. So no matter what you eat, it seems that some types of cells would feel deprived unless the body had a way to divvy up energy sources among organs and cells and also had alternatives when necessary. As a result, the inter-organ exchange of fuel is both complex and dynamic. Here are a few simple tastes of the complexity and elegance of this system.

Muscle: When we say muscle, we typically mean the things that move our arms and legs, technically called skeletal muscles (which differ in form and function from the cardiac muscle in our heart and also from the third type of muscle (smooth) that lines blood vessels and our gastrointestinal tract). At rest, skeletal muscles prefer fat for fuel, using glucose only when insulin levels are high and blood sugar needs some place to go. During sustained exercise, fat is still the preferred fuel at intensities up to 50-60% of that muscle's maximum continuous effort. Above 60% of maximum effort, glucose (or stored glycogen) progressively assumes a dominant role, although this dominance is attenuated when individuals are given a few weeks to adapt to a low carbohydrate diet[23, 271. Also at these higher intensities, some of this glucose is not completely metabolized but is partially broken down to lactate and released back into the bloodstream rather than being oxidized in muscle mitochondria all the way to CO, and water. By contrast, during resistance exercise (very high intensity, brief duration), most of the fuel use consists of glucose made into lactate.

But here's the interesting part. Lactate has a had reputation as a cause of muscle fatigue and pain. This is a classic case of guilt by association. During transition from rest to intense exercise, the increased production of lactic acid rapidly disassociates into lactate and hydrogen ion. It is the accumulation of hydrogen ion, not lactate per se, that contributes to fatigue due to acidosis. Lactate has a much more interesting and positive role to play in the human body. Much of the lactate released from muscle during exercise gets taken up by the liver and made back into glucose (a process called gluconeogenesis) and sent back to the muscles where it can be made into lactate again. And because the liver uses mostly fat to power gluconeogenesis, this shuttle of glucose out from the liver and lactate back (called the Cori cycle) actually ends up powering resistance exercise from energy released by fat oxidation in the liver.

Heart: The predominant fuel preferred by your heart when you are not exercising is fat. The heart rarely uses much glucose, with the only exception being during a heart attack when a vessel is plugged and the oxygen supply to that part of the muscle is cut off or severely reduced. In that case, the small amount of glycogen in heart muscle is used anaerobically to make lactate. And here's one more bit of heresy about lactate. During exercise, a healthy and well-perfused heart actually takes up lactate from the circulation and burns it to CO2 and water. Lactate is preferred by heart muscle cells over glucose, and during endurance exercise, lactate can provide as much as 50% of your heart's energy need [28].

Liver: The liver does a whole lot of important things for the rest of the body, such as making, storing, and releasing glucose when necessary,making ketones when carbohydrate intake is restricted for more than a few days, collecting and secreting fats and lipids as lipoproteins, and making and secreting a number of important blood proteins. As a result, the liver uses a lot of energy for an organ its size, and most of the energy it uses comes from fat. The liver can get the fat it needs from circulating fatty acids released from fat cells, from remnant lipoproteins it removes from the circulation, or by making fat from carbohydrates (lipogenesis).

Brain: The brain is the spoiled child of the organ family. It can burn glucose or ketones (or a combination of the two) and it can't burn fat. This is interesting because the brain itself contains a lot of fatty acids in all its membranes and myelin (although little or none as triglycerides), and the many types of brain cells all contain mitochondria that should be capable of oxidizing fatty acids. Another surprise about the brain is how much energy it consumes each day (600 kcal) despite weighing just 3 pounds. This is more than 10-times the average energy use per pound of the rest of the body, which explains why the brain has such a large blood supply (to provide fuel and oxygen and also to keep it cool).

The other important fact about the brain's fuel supply is that it contains no reserve supply of glycogen, and because it can't burn fat, it is absolutely dependent upon a minute-by-minute blood supply containing both fuel and oxygen to meet its needs. This is why even a transient drop in blood sugar causes an intense physiological response (increased heart rate, shaking, anxiety, and intense hunger/cravings). And if blood sugar suddenly drops to less than half of the lower limit of normal, it causes coma. The shaking, anxiety, and fast heart rate that occur when blood glucose levels fall are due to a dramatic increase in adrenergic nervous system activity (release of nor-adrenaline from nerve endings) and adrenaline from the adrenal glands. Among other effects, this acute response to hypoglycemia stimulates two processes in liver: the breakdown of any glycogen present and formation of glucose from anything available (lactate or amino acids from protein).

Understanding this combination of facts helps explain why rapid weight loss diets, especially those emphasizing carbohydrates, can be tough to follow. If for example you decide to eat 1200 kcal per day, composed of 25% protein (75 grams), 25 % fat, and 50% carbohydrate, your daily carb intake totals just 600 kcal. That's more than enough to prevent your liver from making ketones, but it's just barely enough to feed your brain. But, you say, your liver can also make glucose from some of the protein via gluconeogenesis, which is correct, but that totals less than 50 grams (200 kcal) per day. Still, this 1200 kcal diet should support your brain's fuel needs just fine.

But what happens if you decide to go jog 5 miles in 50 minutes (which consumes 100 kcal per mile). Even at this relatively slow pace of 6 miles per hour, about half of your muscle fuel use will come from glucose or glycogen, so you burn about 250 kcal of carbohydrate fuel. In this scenario, in the 24-hours that includes this exercise, the 600 + 250 kcal of glucose use exceed the 600 + 200 kcal available supply. Typically in this setting, people start to feel lousy (see "bonking" below). Your body can make up the difference by drawing down its limited glycogen reserves or by the net breakdown of some muscle to increase liver gluconeogenesis. But if you stick to the diet and continue the daily exercise, something's got to give. And what typically happens is that your instincts (only a masochist likes to feel bad day after day) get the upper hand over your best intentions, prompting you to either eat more or exercise less.

In this situation, it would be convenient if this fuel conundrum could be solved by your liver making some ketones from body fat to help fill the gap in the brain's fuel supply. However, this appears to be a flaw in human design because liver ketone production does not kick in until daily carbohydrate intake is consistently at or under 50 grams (200 kcal) per day for a number of days. Thus there appears to be a functional gap in the body's fuel homeostasis when dietary carbohydrate intake is consistently somewhere between 600 and 200 kcal per day.

So let's consider an alternative diet, say 1200 kcal consisting of 30% protein, 15% carbs (i.e., 180 kcal or 45 grams), and 55% fat. After a week or two of getting adapted (during which you may experience some of the fuel limitation symptoms discussed above), your serum ketones rise up in the range (1-2 millimolar) where they meet at least half of the brain's fuel supply. Now if you go for that 5 mile run, almost all of your body's muscle fuel comes from fat, leaving your dietary carb intake plus gluconeogenesis
from protein to meet the minor fraction of your brain's energy need not provided from ketones. And, oh yes, after your run while on the low carb diet, your ketone levels actually go up a bit (not dangerously so), further improving fuel flow to your brain.
So what does this mean for the rest of us who are not compulsive runners? Well, this illustrates that the keto-adapted state allows your body more flexibility in meeting its critical organ energy needs than a 'balanced' but energy-restricted diet. And in particular, this also means that your brain is a "carbohydrate dependent organ" (as claimed by the USDA Dietary Guidelines Advisory Committee as noted in Chapter 3) ONLY when you are eating a high carbohydrate diet. When carbohydrate is restricted as in the example above, your body's appropriate production of ketones frees the brain from this supposed state of 'carbohydrate dependency' And because exercise stimulates ketone production, your brain's fuel supply is better supported during and after intense exercise when on a low carbo-hydrate diet than when your carbohydrate intake is high

Here is the relevant information about the problem of increasing your energy intake from protein alone:

[W]hen a person makes the transition from weight loss to weight maintenance on a low carbohydrate diet, total energy intake must increase. Carbohydrate necessarily remains a small fraction of one's dietary energy supply in order to remain in a keto-adapted state and avoid the side effects of carbohydrate intolerance. Therefore, the proportion of fat to protein in the diet needs to be increased to avoid overeating protein.[...]

One could eat more protein than this, but there's no metabolic reason why this would be beneficial, and a variety of data indicate that too much protein causes malaise or worse (see sidebar). Even in the context of a weight maintenance very low carbohydrate diet, as the proportion of protein is increased above 30% of calories, there is a marked increase in blood urea nitrogen[126]. Fat costs less and is more satiating, and we've demonstrated that even vigorous athletes on low carb do just fine when just 15% of their energy intake comes from protein.

[Side Bar]
Human Protein Tolerance

The upper limits of human protein tolerance have not been rigorously defined. However that's not to say that this topic is completed unexplored. The Inuit knew to keep their protein intake moderate to avoid the lethargy and malaise that they knew would occur if they ate more protein than fat. Stefansson, during his year in the Bellevue experiment, was encouraged by the study investigators to eat a high protein diet for the first few weeks, causing him to be weak and sick to his stomach[11]. Finally, the Swedish investigators who developed the carbohydrate-loading hypothesis in the 1960's used lean steak as the principal food for their low-carb diets, and they had trouble keeping subjects on such a diet for more than 10 days.

Another way to examine upper limits of protein tolerance is to examine the effect of protein meals varying in amount on muscle protein synthesis. Dose response studies indicate a linear increase in skeletal muscle protein synthesis with ingestion of high quality protein up to about 20-25 grams per meal[127]. With protein intakes twice this amount, there is a marked increase in protein oxidation with no further increase in protein synthesis. When looked at over the course of a day, there is no credible evidence that protein intakes above 2.5 g/kg body weight lead to greater nitrogen balance or accumulation of lean tissue.

Another reason to avoid eating too much protein is that it has a modest insulin stimulating effect that reduces ketone production. While this effect is much less gram-for-gram than carbohydrates, higher protein intakes reduce one's keto-adaptation and thus the metabolic benefits of the diet.

As a result of these observations, plus our studies of muscle retention and function during carbohydrate restriction[27, 78, 87], we recommend daily protein intakes between 1.5 and 2.5 gram per day per kg of reference weight[5]. For a person on a weight maintaining low carbohydrate diet, this typically translates to somewhere between 15% and 25% of your daily energy intake coming from protein.

The issue of proteins being bad for your kidneys is addressed rather nicely in the following quote:

Issue: I have heard that diets like Atkins which are low in carbohydrate and high in protein may cause my bones to weaken and my kidneys to fail.

Response: First of all, a well-formulated low carbohydrate diet like Atkins is not really that high in protein. We recommend protein between 1.5 and 2.0 grams per kilogram reference body weight (0.7 to 0.9 grams per pound reference weight). This translates to between 90 and 150 grams per day for a range of adults, which is about what the average adult in the US is already eating. This level is well tolerated and is not associated with adverse effects on bone, kidney or other health indicators. The reason that protein intakes higher than the minimum recommended (0.8 grams per kilogram) were thought to negatively impact bone is because they cause a small but measureable increase in urinary calcium excretion. On the surface, this could indicate a higher risk for bone loss over time and development of osteoporosis. However, we now know that increasing dietary protein above the minimum also causes greater intestinal absorption of dietary calcium, which balances the slightly greater calcium loss in the urine. In fact, recent research suggests that diets higher in protein are associated with healthier bones as people age.
Similar to the situation with bone health, the concern about kidney problems stems from a belief that high protein diets contribute to renal disease. This belief is based on studies of restricting protein in people who already have severely damaged kidneys.

However, there is no data link¬ing the moderate protein intake range listed above to damage in people with normal kidney function. In technical terms, despite some evidence that higher protein intakes can increase glomerular filtration rate, the evi¬dence linking this normal physiologic response to progressive loss of kid¬ney function in healthy people is completely lacking. [...]

Protein and Kidney Function — Lessons from Kidney Donors

In the past 50 years, tens of thousands of individuals with two healthy kidneys have donated one of them to save another's life. As a result, there are currently about 100,000 people in the US with only one kidney, with some of them surviving this way since the 1970s. None of these people are advised to eat less protein, even though they have only half as much kidney function. What this effectively does is double their protein intake relative to kidney function. Yes, the remaining kidney does get a bit bigger, but it doesn't come close to doubling in size.

Recently, within this population, only 65 have developed kidney failure and needed a transplant of their own over an approximately 3-year period. This is about half the average rate of kidney failure in the gen-eral population. And here's the kicker — most of these people gave a kidney to a relative who needed one, and the most common causes of kidney failure run in families. Based on that, we'd expect the donors to have more cases of kidney failure than the general population. This is a head-scratcher, but clearly this indicates that dietary protein is not a big killer of kidneys.

That said, dietary protein restriction is a recognized factor in preserving residual glomerular function in individuals with advanced kidney failure, but the value of extremely low protein diets in this situation remains a topic of ongoing debate. However, the extrapolation of this extreme clinical example to the presumption that dietary protein in the ranges discussed above is a primary cause of renal disease is completely unfounded.

 

[Gaby]

Another important concept from "The Art and Science of Low Carbohydrate Living" (well, the whole book is really important!) is how we need less Omega 3s when we are having higher intakes of saturated fats:

[T]he type of fat eaten when most of your energy comes from fat is important. If you are a hunter getting 70-80% of your energy from fat, your dietary fat composition needs to be different from what you would consume if you were a subsistence farmer eating mostly carbohydrates with just 15% of your energy as fat. When fat is used for fuel, the body prefers that the majority of it be provided as mono-unsaturates and saturates. On a low carbohydrate diet appropriately rich in fat, even if only a small proportion of your fat is polyunsaturated, this small fraction times the total amount will still provide enough grams of the essential fatty acids. Because they function like vitamins rather than fuel, for the essential fatty acids, it's all about dose, not percent. And for the omega-6 fats in particular, more is not necessarily better.

[...]But perhaps equally (if not more) important is the dramatic change in how our bodies handle polyunsaturated fats when we cut back on carbohydrate intake. Polyunsaturates are obligate components of phospholipids, which in turn are needed to construct the membranes that enclose our cells and regulate cellular functions. Getting the right amount of polyunsaturated fats into membranes is critical for life-defining processes such as glucose transport (i.e., insulin sensitivity), controlling inflammation, salt excretion, blood pressure control, egg release from ovarian follicles, and sperm motility.

[...][Y]our body has a remarkable ability to select what it wants to keep while burning off the rest. It also means that you can selectively store specific fatty acids in specific places. Thus the mix of fats found in membrane phospholipids is dramatically different from that found in the triglycerides stored in adipose tissue. And even the mix of fatty acids in our adipose tissue triglycerides varies from site to site. For example, the fat composition in your legs is different from the mix found around your abdomen [67]. So the next time you hear someone argue a point by stating "you are what you eat", be sure to treat that person's opinion with a healthy dose of skepticism.[...]

The Polyunsaturated Fatty Acid Response to Carbohydrate Restriction

Most serious scientists avoid the topic of polyunsaturated fatty acid (PUFA) metabolism like a plague. Why? Because it's a tangle of obscure names and symbols, parallel metabolic pathways, and positional isomers with conflicting functions. And besides, there are so many of them! In a single serum fraction, we typically identify about 20 different fatty acids with two or more double bonds (the definition of a polyunsaturate) belonging to 3 different metabolically distinct families (for details, see post-script below).

So again, it is fair to ask, what's the upside of opening this metabolic can of worms? The answer, simply, is that the dramatic changes in PUFA associated with adapting to a low carbohydrate diet can help explain the underlying physiology of its benefits.

First, we'll offer you an overview of why that might be. Then we'll tell you how we stumbled into this understanding over the last 20 years.

Point 1. Low carbohydrate diets cause the physiologically important end-products of essential fatty acid (EFA) metabolism in membranes to go up sharply[29, 41, 42]. EFA end-products in muscle membranes are positively correlated with insulin sensitivity[38]. Thus these membrane composition changes can explain the improved insulin sensitivity that occurs when an insulin resistant individual adopts a low carbohydrate diet.

Point 2. Increased EFA end-products in liver membranes shut down expression of the enzymes that drive lipogenesis [fat accumulation][72]. [...] In addition, this helps explain the dramatic reduction in serum triglycerides that we see in individuals with metabolic syndrome who go on a low carbohydrate diet.

Point 3. A simple explanation for increased EFA end-products might be that the body makes more of them on a low carb diet. But unfortunately it isn't that simple. All of the data (levels of metabolic intermediates and enzyme activities) point in the opposite direction — that production of EPA end-products goes down! So if they go up without more being made, this indicates that the body must be destroying them more slowly. And since the arch-enemy of PUFA is a group of molecules we call free-radicals (or more precisely, reactive oxygen species — ROS), perhaps the rate of ROS generation is reduced when dietary carbohydrates are restricted. The mainstream consensus still regards this as an 'outside the box' (or should we say "radical") fantasy, but it is also consistent with our multiple observations that a host of biomarkers of inflammation (known inducers of ROS generation) go down when a low carb diet is adopted [29].

So there you have it. It's really kind of elegant. Inflammation driven by the forced metabolism of carbohydrate drives up the production of ROS in mitochondria. ROS damage membrane EFA end-products, which at some point can't be replaced fast enough. The resultant reduction in membrane EFA end-products unleashes the genes (e.g. fatty acid synthase) that control liver lipogenesis, and at the same time the loss of membrane HUFA [highly unsaturated fatty acids (HUFA; e.g., arachidonate and docosahexaenoate [DHA])] causes increased insulin resistance in muscles. Insulin resistant muscles take up less glucose, resulting in more of it being diverted to the liver for lipogenesis. Take away the high levels of ROS and membranes suffer less damage, their content of EFA end-products rises, and both dyslipidemia and insulin resistance improve. The trigger for this set of metabolic dominos — the switch that controls this process — is dietary carbohydrate.

Summary

Clearly there is much more to dietary fats and health than is contained in simplistic edicts like "saturated fats are bad for you". We have shown you that our bodies respond to saturated fats very differently when we are keto-adapted, such that they are rapidly burned for fuel rather than being stored. By contrast, people eating higher levels of dietary carbohydrates, even when they are not over-eating total calories, have higher blood levels of saturated fats. [...]

The other new and important insight into the fatty acid response to carbohydrate restriction comes from examining the changes in EFA end-products in phospholipids. Keto-adaptation results in marked changes in how our bodies are able to construct and maintain optimum membrane composition, and this appears to be due to less production of ROS and inflammatory mediators. There is much more for us to learn about this process, but at the very least, this observation helps explain the improvement in insulin sensitivity that occurs when you become keto-adapted.

[...] Polyunsaturated oils rich in essential fats are important dietary constituents when one is eating a low fat diet. However if one is eating lots of fat, to get the same absolute amount of essential fats, a much smaller proportion of polyunsaturated fats (both omega-6 and omega-3) will suffice. Second, we have demonstrated in both human and animal studies that a low carb diet is associated with increased levels of essential fatty acid products (i.e., arachidonate and DHA) in blood phospholipids and tissue membranes. This occurs without signs of an increase in production, suggesting that their rate of degradation goes down when dietary carbs are limited. Thus the human requirement for essential fatty acid products may actually be somewhat reduced on an aboriginal hunting diet.

 

[Thor]

Here is a quote from "The Art and Science of Low Carbohydrate Living" to see which fuel our organs prefer to use as an energy source. The key is to have fatty meats in order to have an energy intake of around 70% coming from fat. If you increase the energy intake from proteins alone (lean meats), and not fats, it will not be the same and you might actually get sick.

... snip...

As a result of these observations, plus our studies of muscle retention and function during carbohydrate restriction[27, 78, 87], we recommend daily protein intakes between 1.5 and 2.5 gram per day per kg of reference weight[5]. For a person on a weight maintaining low carbohydrate diet, this typically translates to somewhere between 15% and 25% of your daily energy intake coming from protein.

Psyche, thanks so much for this post. I have been spending a lot of time to find out how much protein, and fat to eat, given my upper limit of 20 g of carbs at the moment.

Given the assumptions stated above, namely that we 70% of our energy intake to come from fat and that our protein intake should be 1.5-2.5 times our weight in kg's, we can derive some equations for recommended weights of protein, carbs and fat based on our body weight.

First we need a little notation. Let

Wp = the grams of protein you eat in a day
Wc = the grams of carbs you eat in a day
Wf = the grams of fat you eat in a day

Wkg = your body weight in kg's

Bearing in mind that the energy derived from one g of fat is twice that of one g of protein and also one g of carbs, and shifting things around a bit we get:

Wf = 7/6 x (Wp + Wc)

and since we know that the recommended range of protein intake is 1.5-2.5 our body weight in kilos we can derive the recommended limits of fat intake given our body weight:

Recommended fat at recommend low protein limit: Wf = 7/6 x (1.5 x Wkg + Wc)

Recommended fat at recommended high protein level: Wf = 7/6 x (2.5 x Wkg + Wc)


To give an example, I weigh 72 kilos and want to eat 20 g of carbs. How much protein and fat should I eat?

Recommended fat at recommend low protein limit:

Wf = 7/6 x (1.5 x Wkg + Wc) = 7/6 x (1.5 x 72 + 20) = 149 g

Recommended fat at recommended high protein level:

Wf = 7/6 x (2.5 x Wkg + Wc) = 7/6 x (2.5 x 72 + 20) = 233 g

This means that I have actually eaten too much fat and too little protein but I guess it's better than the other way around :)

Edit: changed protein range to reflect quoted range

 

[Jacques]

Here is a quote from "The Art and Science of Low Carbohydrate Living" to see which fuel our organs prefer to use as an energy source. The key is to have fatty meats in order to have an energy intake of around 70% coming from fat. If you increase the energy intake from proteins alone (lean meats), and not fats, it will not be the same and you might actually get sick.

... snip...

As a result of these observations, plus our studies of muscle retention and function during carbohydrate restriction[27, 78, 87], we recommend daily protein intakes between 1.5 and 2.5 gram per day per kg of reference weight[5]. For a person on a weight maintaining low carbohydrate diet, this typically translates to somewhere between 15% and 25% of your daily energy intake coming from protein.

Psyche, thanks so much for this post. I have been spending a lot of time to find out how much protein, and fat to eat, given my upper limit of 20 g of carbs at the moment.

Given the assumptions stated above, namely that we 70% of our energy intake to come from fat and that our protein intake should be 1.5-2.0 times our weight in kg's, we can derive some equations for recommended weights of protein, carbs and fat based on our body weight.

Shouldn't it be 1,5-2,5 ?

First we need a little notation. Let

Wp = the grams of protein you eat in a day
Wc = the grams of carbs you eat in a day
Wf = the grams of fat you eat in a day

Wkg = your body weight in kg's

Bearing in mind that the energy derived from one g of fat is twice that of one g of protein and also one g of carbs, and shifting things around a bit we get:

Wf = 7/6 x (Wp + Wc)

How did you manage to find that equation ?

 

[Gaby]

This means that I have actually eaten too much fat and too little protein but I guess it's better than the other way around :)

I'm probably having more fats than protein as well :)

As long as we are having fatty meats, without leaving the fatty edges behind, we should be safe.

 

[Thor]

Here is a quote from "The Art and Science of Low Carbohydrate Living" to see which fuel our organs prefer to use as an energy source. The key is to have fatty meats in order to have an energy intake of around 70% coming from fat. If you increase the energy intake from proteins alone (lean meats), and not fats, it will not be the same and you might actually get sick.

... snip...

As a result of these observations, plus our studies of muscle retention and function during carbohydrate restriction[27, 78, 87], we recommend daily protein intakes between 1.5 and 2.5 gram per day per kg of reference weight[5]. For a person on a weight maintaining low carbohydrate diet, this typically translates to somewhere between 15% and 25% of your daily energy intake coming from protein.

Psyche, thanks so much for this post. I have been spending a lot of time to find out how much protein, and fat to eat, given my upper limit of 20 g of carbs at the moment.

Given the assumptions stated above, namely that we 70% of our energy intake to come from fat and that our protein intake should be 1.5-2.0 times our weight in kg's, we can derive some equations for recommended weights of protein, carbs and fat based on our body weight.

Shouldn't it be 1,5-2,5 ?

First we need a little notation. Let

Wp = the grams of protein you eat in a day
Wc = the grams of carbs you eat in a day
Wf = the grams of fat you eat in a day

Wkg = your body weight in kg's

Bearing in mind that the energy derived from one g of fat is twice that of one g of protein and also one g of carbs, and shifting things around a bit we get:

Wf = 7/6 x (Wp + Wc)

How did you manage to find that equation ?

Gandalf, fair question. You could also use 1.5-2.5 (which is actually the numbers I quoted myself ). The range 1.5-2.0 is mentioned elsewhere in the same post from Psyche from the same authors and I just did the math using 1.5-2.0. Anyway, I assume there is some flexibility here. I see that the reference is confusing and I will edit it to reflect the 1.5-2.5 range.

As to how I derived the equation, I was fearing someone would ask that as the notation is a bit cumbersome to write. In the following, I use a simpler notation. Not as elegant, but the meaning is the same.

Let

Wp = Weight of protein in grams
Wc = Weight of carbs in grams
Wf = Weight of fat in grams

Ep = Energy from protein =4Wp
Ec = Energy from carbs = 4Wc
Ef = Energy from fat = 9Wf

Therefore we get total Energy
E = Ep + Ec + Ef = 4Wp + 4Wc + 9Wp

We know that the 70% of energy intake should come from fat and consequently that 30% should come from protein and carbs.

(Ep +Ec)/E = 30%

(Ep + Ec)/(4Wp + 4Wc + 9Wp) = 0.3

Ep + Ec = (4Wp + 4Wc + 9Wf)*0.3

4Wp + 4Wc = (4Wp + 4Wc + 9Wf)*0.3

4Wp + 4Wc = (4Wp + 4Wc)x0.3 + 2.7Wf

0.7(4Wp + 4Wc) = 2.7Wf

Wf = 2.8/2.7(Wp + Wc)

Wf = 1.04(Wp + Wc)


Edit: corrected numbers to reflect correct nutritional values

 

[Jacques]

Thank you Thor for the explanations.

If I may, i would have another question.

Ep = Energy from protein =17Wp
Ec = Energy from carbs = 17Wc
Ef = Energy from fat = 34Wf

Are those equations an hypothesis or are they real values ?

Sorry if I missed them in the book.

 

[Thor]

Thank you Thor for the explanations.

If I may, i would have another question.

Ep = Energy from protein =17Wp
Ec = Energy from carbs = 17Wc
Ef = Energy from fat = 34Wf

Are those equations an hypothesis or are they real values ?

Sorry if I missed them in the book.

I am glad that you asked the question. I had just looked them up earlier today and now, when I rechecked to answer this post, it turns out that my recollection was off. It should be

Ep = 4 Wp
Ec = 4 Wc
Ef = 9 Wf

It doesn't change things a whole lot as the ratio is still close to 1:1:2 - which I thought I had read earlier in the thread, but I can't find it now. However, it does change things a little bit so now the equation should be

Wf = 1.04 x (Wp + Wc)

Thanks for making me double check the equation :) I'll edit the equations above later today to reflect this. The link to the energy values for protein, carbs and fat is here: http://www.brianmac.co.uk/nutrit.htm

 

[Jacques]

Thank you Thor for the explanations.

If I may, i would have another question.

Ep = Energy from protein =17Wp
Ec = Energy from carbs = 17Wc
Ef = Energy from fat = 34Wf

Are those equations an hypothesis or are they real values ?

Sorry if I missed them in the book.

I am glad that you asked the question. I had just looked them up earlier today and now, when I rechecked to answer this post, it turns out that my recollection was off. It should be

Ep = 4 Wp
Ec = 4 Wc
Ef = 9 Wf

It doesn't change things a whole lot as the ratio is still close to 1:1:2 - which I thought I had read earlier in the thread, but I can't find it now. However, it does change things a little bit so now the equation should be

Wf = 1.04 x (Wp + Wc)

Thanks for making me double check the equation :) I'll edit the equations above later today to reflect this. The link to the energy values for protein, carbs and fat is here: http://www.brianmac.co.uk/nutrit.htm

Thanks again Thor.

From the link, we can read ;

The energy yield per gram is as follows: Carbohydrate - 4 Calories, Fats - 9 Calories and Protein - 4 Calories.

So for 1 gram of carb we have 4 calories. (1Wc = 4 calories or 4Ec)

And you say :

Ec = Energy from carbs = 4Wc

which to my understanding means that 1 energy equals 4 grams of carbs.

So if Energy is the same thing as Calories, the two equations are not similar ?

Am I confusing energy and Calories

 

[NewOrleans]

I'd been very good about changing my diet. Somehow I found successful mental resolve to place in my daily food choices: "just say no" to certain foods. It's corny, I know, but it works for me.
So, I'm up at 5 AM this morning up feeding the hungry cat with one eye open and I broke off a piece of good French bread I had completely abstained from yesterday, and then, quite mechanically, I put a bread in my mouth. No sooner than I had a mouthful of bread, I woke up - cheeks puffed out like a chipmunk - and spit it out into the trash.

I'm getting better, I didn't swallow.

 

[Aiming]

...and then, quite mechanically, I put a bread in my mouth. No sooner than I had a mouthful of bread, I woke up - cheeks puffed out like a chipmunk - and spit it out into the trash.

I'm getting better, I didn't swallow.

LOL, that was rescue at the last second - good job! :D

My fatigue and weakness are gone now. But I've tested two types of nuts for a snack and didn't tolerate them, so my energy levels are not as they could be. I don't crave carbohydrates anymore (not even fantasizing), I've simply lost interest. :)

I've also learned that I've eaten too much fat, which is why I put on weight. Apparently those extra portions of fat are only for the thin types but not for those who gain weight easily.

 

[aragorn]

Thanks again Thor.

From the link, we can read ;

The energy yield per gram is as follows: Carbohydrate - 4 Calories, Fats - 9 Calories and Protein - 4 Calories.

So for 1 gram of carb we have 4 calories. (1Wc = 4 calories or 4Ec)

And you say :

Ec = Energy from carbs = 4Wc

which to my understanding means that 1 energy equals 4 grams of carbs.

So if Energy is the same thing as Calories, the two equations are not similar ?

Am I confusing energy and Calories

I think what you're confusing is that the noted 'Ec' is just the total amount of energy (in Calories) produced by the carbs, there's no amount "attached" to the 'Ec'. You could think it as: Ec-total[Calories]=4[Calories/gram]*Wc[gram]. Multiplying the units on the right side of the equation gives you Calories: Calories/gram*gram=Calories.

It would have been clearer if Thor had included the units in the equations, osit. ;)

 

[Bluestar]

First we need a little notation. Let

Wp = the grams of protein you eat in a day
Wc = the grams of carbs you eat in a day
Wf = the grams of fat you eat in a day

Wkg = your body weight in kg's

Bearing in mind that the energy derived from one g of fat is twice that of one g of protein and also one g of carbs, and shifting things around a bit we get:

Wf = 7/6 x (Wp + Wc)

Thank you Thor. This has helped very much. I spent a half a day trying to go over how much fat I need to eat. Being my math is very, very rusty, I was hitting a dead end.

From this formula at 50kg body weight I get the following results:
Fat = 111g
Protein = 99g
carbs = 20g

The fat to protein ratio looks high...? Thought it was a 2:1 ratio...? Thanks again