Competition for Calories

Here is a very new paper which has an interesting way of looking at nutrient partitioning (Archer Edward, Pavela Gregory, McDonald Samantha, Lavie Carl J., Hill James O. Cell-Specific “Competition for Calories” Drives Asymmetric Nutrient-Energy Partitioning, Obesity, and Metabolic Diseases in Human and Non-human Animals. Frontiers in Physiology, v9:2018, 1053):

…we posit that the chronic positive energy balance (i.e., over-nutrition) that leads to obesity and metabolic diseases is engendered by apparent deficits (i.e., false signals) driven by the asymmetric inter-cellular competition for calories and concomitant differential partitioning of nutrient-energy to storage. These frameworks, in concert with our previous theoretic work, the Maternal Resources Hypothesis, provide a parsimonious and rigorous explanation for the rapid rise in the global prevalence of increased body and fat mass, and associated metabolic dysfunctions in humans

Obesity and Diabetes

There’s a common definition of the word “obese”. We think of people who are really fat as being obese. I was one of them. 

What is Obesity?

Obesity has a technical definition which is somewhat arbitrary. It is a function of weight and height and is known as BMI (Body Mass Index). The US government definition is (NCHS Data Brief ■ No. 288 ■ October 2017):

Obesity: BMI was calculated as weight in kilograms divided by height in meters squared, rounded to one decimal place.

Obesity in adults was defined as a BMI of greater than or equal to 30.

BMI Weaknesses as a Metric

BMI (and obesity) does not take into account body composition such as body fat or lean body mass.  Two people can have the same BMI and be technically obese and one be solid muscle with little body fat and the other have significantly more body fat.

However, for the “average” person BMI is a decent measurement of fatness.

Obesity and Health

Generally, obesity and health are inversely related but there are people who are obese (by BMI) but are healthy. There are also people who are not obese but have poor health. This observation has led to the concept of personal fat threshold (PFT). This is described in (Taylor R, Holman RR.  Normal weight individuals who develop type 2 diabetes: the personal fat threshold. Clin Sci (Lond). 2015 Apr;128(7):405-10) (PDF).

Personal Fat Threshold (PFT)

The Personal Fat Threshold concept is that there’s a level of fatness which the individual can tolerate before their health is impacted. This concept is tempting but has some problems.

PFT is not all that useful in the a-priori sense. There is no objective test to see if someone is at or near their PFT. Obesity isn’t useful as a metric. Neither is body fat level.

The only use of PFT is to support the medical advice to patients of weight loss as a tool for management of Type 2 diabetes. The PFT concept doesn’t actually contribute much since it has been believed (before the PFT concept was developed) that weight loss of about 15% resolves diabetes (Reversing Diabetes with Weight Loss: Stronger Evidence, Bigger Payoff).

Until there’s an a-priori means of measuring PFT the approach seems to be not all that useful. No medical doctor can tell you that you are 10 lbs away from your PFT. The point is completely hidden until it manifests. All it says that is if you are not technically considered to be obese and you are diabetic it is because you have gone over your personal fat threshold. 

PFT – My Own Experience

There are three lines of reasoning from my own experience that call into question the PFT theory.

One was from my own experience with Insulin as a Type 2 Diabetic. I put on 40 lbs in a short time when I was put on Insulin. Conversely, when I got off Insulin my weight dropped quickly. Teenage females who are Type 1 diabetics and want to lose weight are well aware of this relationship. Weight increases followed Insulin increases (Skovsø S, Damgaard J, Fels JJ, Olsen GS, Wolf XA, Rolin B, Holst JJ. Effects of insulin therapy on weight gain and fat distribution in the HF/HS-STZ rat model of type 2 diabetes. Int J Obes (Lond). 2015 Oct;39(10):1531-8). not Insulin followed weight. Eventually, stasis is reached in weight and Insulin amount – at least in the short term.

Increasing dietary carbohydrates requires pumping more Insulin. When you stop eating dietary carbohydrates you don’t have to inject extra insulin for the meal. 

The second reason was the increase in Insulin that is required over time to maintain blood sugar levels. I started at about 40g of Insulin and had good blood sugar controls. By four later my weight was stable but the amount of Insulin to keep blood sugar stable kept increasing to about 120 units. More particularly, the amount of insulin to cover carbohydrate loads increased. In my own case 1 unit of Insulin could cover 15 grams of carbs when I started Insulin and by four years later 1 unit wasn’t enough to cover 8 grams. All of this was at a stable weight (after the initial gain) and the same level of carbohydrates.

A third reason is my own weight history. I was at 285 lbs and non-diabetic for years. Then I mysteriously lost 50 lbs down to 235 lbs over the course of about six months. This is a common occurrence with Type 2 diabetics (Unexplained Weight Loss and Diabetes). After six months of this unexplained weight loss, I was then diagnosed with diabetes.

Perhaps this is the body pushing back from the PFT but it does call the concept into question – or at least indicate the real issue is much more complicated. After being put on Metformin my weight stabilized at around 10 lbs higher (although Metformin is said to lower weight). As my diabetes got worse my doctor tried different medications some of which added weight and some (like Byetta) caused small weight loss. Finally, the addition of Insulin added 40 lbs to my weight.

I did low carb while on Insulin but it only took my HbA1C down to 6.4. It wasn’t until I did low carb plus Intermittent Fasting that I was able to get off Insulin and my weight fell very quickly. My last HbA1C was 5.2 which is a normal non-diabetic number.

Carbohydrate Insulin Relationship

At the very least, if the PFT concept is salvageable, it needs to be modified for increasing Insulin Resistance levels. If the best treatment for diabetes is weight loss the best way for Type 2 Diabetics to lose weight is to reduce insulin levels. The best way to reduce insulin levels is to the insulin load of the diet. For a Type 2 Diabetic who is on Insulin this results in a loss of a lot of weight in a very short period of time.

The recommendation that losing 15% of body weight does not seem plausible to a diabetic like myself. I’ve lost more than 15% from my peak weight and not been able to control my diabetes. I lost weight with Low Carb by itself but not enough to get off Insulin. At it was more than 15% of weight loss.  If I was told that losing 15% of my body weight would control my diabetes I would have told my doctor that I tried it and it didn’t work.

I lost much less than 15% of my weight in the beginning of Low Carb plus Intermittent Fasting and was able to get off Insulin completely. It was getting off Insulin which allowed me to lose weight. And it was reducing my body’s Insulin needs by the Low Carb diet and Intermittent Fasting which worked for me.

See (Obesity and Insulin Resistance).

The Right Goal

Weight loss alone should never be your goal. Fat loss should be your goal. This can be demonstrated from the numbers. If you have 25% body fat then the weight you want to lose should come out of that 25% of body fat and not from the 75% of lean body mass. If you lose weight and most of the weight comes from your lean body mass you have not done yourself any favors.

Maximum Fat Loss

The fastest way to lose fat is to greatly reduce your carbohydrates and fat intake. Protein should never be reduced. For most people protein should be increased.

Macros for Fat Loss

There is a pretty simple set of macros for maximum body fat loss.

  • Protein at 1 gram per lb of goal weight. 
  • Carbs at less than 30 grams net. 
  • Fat at less than half the grams of protein. 

Macros Calculator

I made a calculator for maximum fat loss. The calculator estimates your current body fat and asks you to say what percentage body fat you want to reach.


The recommended daily protein minimums are pretty low. I suggest much more. If you have normal kidney function that is no problem.

You need enough protein in your diet to replace the protein your body will eat up during the diet. You also need some for gluconeogenesis. Since you will be eating at a caloric deficit any extra protein won’t be a problem – it won’t turn into chocolate cake.

Protein has essential nutrients. Eating 3 grams of Leucine (found in about 30g of protein) is a good goal to hit with every protein meal. That’s around 5 ozs of skinless chicken breast.


Eat the carbs as green leafy veggies. Broccoli is a great choice for micronutrients. You don’t like the taste? Get over it. It’s good for you. And you will eventually grow to like the taste.


If you want to lose fat faster, eat less fat. If you are losing too quickly, eat more fat. The fat you eat doesn’t come off your body. The fat you don’t eat in your diet comes off your body. Any fat you eat is stored on your body very efficiently. Fat has few essential nutrients.

Even a low fat diet is still relatively high fat. The fat is just coming off your body. You can’t stay on a low fat diet forever. You have to increase your fat over time as you reach your goals.

It’s a good idea to take a couple of fish oil capsules every day to get more of the good fats.

Studies on this Diet

This is also known as a variant on the Protein Sparing Modified Fast. It is well studied and effective. The PSMF is often done at very low (20g) of fat.

Ketogenic Infants

From (Settergren G, Lindblad BS, Persson B. Cerebral blood flow and exchange of oxygen, glucose, ketone bodies, lactate, pyruvate and amino acids in infants. Acta Paediatr Scand. 1976 May;65(3):343-53):

Mean values from 12 infants (age 11 days-12 months) were: CBF 69 ml/100 g0min-1; cerebral uptake (in mumoles/100 g-min-1): oxygen 104, glucose 27, acetoacetate 0.9, D-beta-hydroxybutyrate 2.3; cerebral release: lactate 2.4 and pyruvate 0.8. Significant uptake of amino acids was found only for histidine 0.95 and arginine 0.7. Significant correlations between arterial concentration and cerebral exchange were found for: ornithine, arginine, phenylalanine, aspartic acid, serine, glutamine and acetoacetate. CBF and substrate exchange were unrelated to age within the group.

Infants had higher mean CBF and greater uptake of ketone bodies than has been reported in adults.

Low Carb Hypothesis

Low Carb diets often result in greater weight loss than low fat diets – this BLOG has linked to many of these studies.

One explanation hypothesized for the greater weight loss on Low Carb diets is the Low Carb diet is said to have an inherent metabolic advantage. This metabolic advantage should manifest itself in a greater resting energy expenditure. The paper looked at two possible mechanisms – triglyceride cycling and glyceroneogenesis.

The critics of the Low Carb diet say that the advantage is that the comparisons aren’t done by holding protein constant. Overfeeding protein is not the same as overfeeding carbs or fat since protein stimulates 24 hour energy expenditure and fat doesn’t (Overfeeding Protein – Carnivore Diet).

Look to the Science

A short term (6 weeks) small (4 subjects) study was done on obese women to compare the Low Carb and Low Fat diets which held energy (total calories) and protein constant ( Segal-Isaacson CJ, Johnson S, Tomuta V, Cowell B, Stein DT. A randomized trial comparing low-fat and low-carbohydrate diets matched for energy and protein. Obes Res. 2004 Nov;12 Suppl 2:130S-40S). The study concluded that there is no significant differences when controlling for protein.

Our results showed no significant weight loss, lipid, serum insulin, or glucose differences between the two diets. 

The study was a decently formulated study but there were weaknesses:

  • Small study – only 4 subjects
  • No control group
  • Older obese females only
  • Very short duration (6 weeks)
  • Low fat didn’t get super-low (20% of calories from fat)
  • The Low Carb diet results in more weight loss but the study was too small to have statistical power

The good parts of the study were:

  • Controlled feeding
  • Matched total calories and protein – varying carbs and protein
  • Decent protein level (30% of calories)
  • Low carb was 5% of calories – good level
  • Randomized control trial
  • Cross-over design so the subjects ate both foods in random order
  • Starches and fruit were the carbohydrate choices (not jelly beans)
  • Deficit was relatively small (200 calories below REE which is a fairly large amount below TDEE depending on activity level)

At the end of the study they gave the participants the choice to continue on for a year. They were given the choice of the two diets and three of the four participants chose the Low Carb diet. However, the Low Carb participants raised their carbohydrate amount from 5% to 23% over the rest of the study so their weight loss partially reversed. There were several distinct advantages for the Low Carb diet.

Lipids were dramatically reduced on both diets, with a trend for greater triglyceride reduction on the VLC diet. Glucose levels were also reduced on both diets, with a trend for insulin reduction on the VLC diet

This fits my own experiences with protein and Low Carb. I’ve seen people stall for a long time and then break the stall by increasing their protein (and dropping their fat). My conclusion is that the ketogenic diet advantage does come from the higher protein intake of the diet. The diet often causes people to increase their consumption of meat which a high quality food.

Just Eat More Protein?

Protein alone doesn’t produce the same advantage that protein and Low Carb have together. This is shown in studies which substitute carbohydrates for protein (Blatt AD, Roe LS, Rolls BJ. Increasing the protein content of meals and its effect on daily energy intake. Journal of the American Dietetic Association. 2011;111(2):290-294).

This study showed that varying the protein content of several entrées consumed ad libitum did not differentially influence energy intake or affect ratings of satiety over a day. When the appearance, taste, fat content, and energy density were controlled, simply adding meat to lunch and dinner entrées to increase the protein content within commonly consumed amounts was not an effective strategy to reduce daily energy intake.

Sigma Nutrition Radio

Here’s a good program on this subject (SNR #64: Are Low-Carb Diets More Effective For Fat Loss?). tl/dl – Low Carb probably has better adherence than Low Fat diets.

Calories-In and Calories-Out

Does Calories-In and Calories-Out work on Keto? In the last 162 days I have averaged 2391 calories a day. My weight is the same at the end of these 162 days. My total energy expenditure (TDEE) is calculated at 2232 calories a day. This is only 159 calories a day from my TDEE or 7% off the calculated amount and that’s less than half the assumed measurement error in the food (typically assumed to be 15%).

So, yes, I conclude that Calories-In and Calories-Out do fairly closely match. At least in my particular case and macros.

So Why Keto?

Where Keto comes in is that I have maintained a 120 lb loss for the past 5+ months without hunger. My hormones are in balance. My insulin level is kept low. I don’t have the blood sugar roller coaster ride.

Here’s a good podcast covering this subject (Sigma Nutrition Radio #85: What Drives Fat Gain? – Thoughts on CICO, Insulin & Obesity).

Evidence for the Role of Insulin in Weight Gain

Here’s an interesting study which provides evidence for the role of Insulin in Weight Gain (Velasquez-Mieyer P, Cowan P, Arheart K, et al. Suppression of insulin secretion is associated with weight loss and altered macronutrient intake and preference in a subset of obese adults. International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity. 2003;27(2):219-226).

For the entire cohort, significant insulin suppression was achieved with simultaneous improvements in insulin sensitivity, weight loss, and body mass index (BMI). Leptin, fat mass, total caloric intake, and carbohydrate craving significantly decreased.

When grouped by BMI response, high responders (HR; ΔBMI < −3 kg/m2) and low responders (LR; ΔBMI between −3 and −0.5) exhibited higher suppression of CIRgp and IAUC than nonresponders (NR; ΔBMI > −0.5). CISI improved and significant declines in leptin and fat mass occurred only in HR and LR.

Conversely, both leptin and fat mass increased in NR. Carbohydrate intake was markedly suppressed in HR only, while carbohydrate-craving scores decreased in HR and LR. For the entire cohort, ΔBMI correlated with ΔCISI, Δfat mass, and Δleptin. ΔFat mass also correlated with ΔIAUC and ΔCISI.

In a subcohort of obese adults, suppression of insulin secretion was associated with loss of body weight and fat mass and with concomitant modulation of caloric intake and macronutrient preference.

From the body of the study:

The role of increased carbohydrate craving and intake has been previously suggested to play a contributory role in the development of obesity. However, the connection between insulin and carbohydrate craving and intake is less clear. The frequent intake of highly refined carbohydrates may induce weight gain by initiating and sustaining a chronic state of hyperinsulinemia. Carbohydrate intake stimulates insulin secretion, raising circulating insulin levels, which in turn favors increased fatty acid uptake, lipid biosynthesis, and inhibition of lipolysis, leading to energy storage.

Conversely, it had been suggested that insulin stimulates hyperphagia and fosters carbohydrate cravings, producing increased levels of insulin that promote insulin resistance and exacerbation of the hyperinsulinemic condition. This suggests that a vicious cycle is set in motion that perpetuates hyperinsulinemia and weight gain, and that breaking this cycle can promote weight loss.


Carbs are Fat Sparing

Our bodies burn carbs in preference to fats. That is because we only have a limited amount of storage for carbs and we have a very high capacity for fat storage. 

We are typically burning some mixture of both fat and carbs (except at extremes). The amount of carbs we are burning is strongly influenced by the amount of carbs we have eaten. If you ate nothing but carbs and ate them at an amount matching your total energy expenditure you will pretty much just burn carbs. 

Since most people don’t eat in their sleep there’s some point where the carbs go down and the body starts to draw from the carb stores, aka, glycogen. That can last as long as a day or so but as the glycogen stores draw down the body starts to shift to fat burning. This is known as glycogen sparing.

On a low carb diet our fuel mixture shifts to largely fat based. At very low levels of Insulin that come with a reduction in carbohydrates, our peripheral cells resist the small amount of glucose we produce and we spare the glucose for the parts of our body which rely on glucose for fuel. This is how the low carbohydrate diet is glucose/glycogen sparing.

A high carb diet is fat sparing since it spares our body fat from being burned and reduces the amount of time that glycogen stores are being drawn down. 

Blood Sugar Rises

It is common and well documented by Cahill in his landmark studies on starvation that at the start of carbohydrate restriction blood sugar often goes up in the first few days before it starts to drop.

I’ve seen this myself with long fasts (greater than 4 days). The first few days result in your body making a lot of glucose in spite of low carbs in your diet.

It takes several days for your ketone production to kick in. That’s why the body dumps glucose.

I’ve also noticed an association between weight loss and blood sugar. My blood sugar is often up on the day before I drop in weight. In reverse, my blood sugar is lower when my weight goes up.