Elevating Insulin And Minimizing Fat Intake With A High-Carbohydrate Diet: The Key To Maximum Nutrient Partitioning
Overview
The goal of body recomposition is to increase net protein deposition, while minimizing net fat deposition. This post will detail how the MNP diet (very high carbohydrate, very low fat, moderate protein) works with the basic physics of macronutrient metabolism to achieve Maximum Nutrient Partitioning.
Obviously, the major factor influencing body composition is net energy balance (energy intake minus energy expenditure). Overfeeding studies confirm basic physics: any energy surplus is deposited, with 75-95% efficiency, as some combination of glycogen, protein and fat. But what most people don't understand is that the ratio of macronutrients in the diet has a large influence on exactly how much, and in what form, excess energy is stored. For example, studies even show that net protein gain can occur at the same as net fat loss. This is because the efficiency of energy deposition varies with each unique macronutrient. These nuances tend to be ignored, oversimplified or completely misunderstood, but once you understand them you unlock the secrets to optimal body recomposition.
Carbohydrates Versus Fat
Since glycogen stores are limited to about 2 pounds (for a fit male), over the long term calories consumed above total energy expenditure are mainly stored as either protein or fat. But here's the catch: when you eat a gram of fat, it is already in the chemical form of storage. Thus an impressive 95% of its energy is deposited. Excess carbohydrates, on the other hand, must be converted via De Novo Lipogenesis into fat. This deposits only 75% of the initial carbohydrate energy. In addition, the body only turns carbohydrates into fat when glycogen stores are overloaded (either because stores are full or because quick-digesting simple sugars have momentarily overcome the body's rate of CHO processing). And because DNL is inefficient, the body prefers to directly burn the energy than convert it to fat. All these factors help explain why eating fat is the best way to gain fat. Overfeeding studies show a clear pattern: whenever high fat and high carbohydrate overfeeding are compared isocalorically (same total kcal), the high fat diet leads to greater fat deposition (and also slightly less protein deposition). In the words of Dr. McDougall: "the fat you eat is the fat you wear."
Although carbohydrate overfeeding is significantly less efficient than fat overfeeding (i.e., more of the total energy is dissipated as heat loss), for the goal of MNP this is actually a good thing. If the goal is to get fat: overfeed fat. But if the goal is to gain muscle and minimize fat, the ideal diet must be a very high carbohydrate, very low fat diet. The is because carbohydrates stimulate the release of the anabolic hormone insulin. Insulin pushes both fat and protein into storage. Since the goal of MNP is to push protein (but not fat) into storage, the ideal solution is to eat a high-calorie, high carbohydrate, but very low fat diet.
The Oxidative Hierarchy
Metabolism studies use this term to describe the body's preference for oxidizing macronutrients. Alcohol is considered "perfect" and is at the top. This is because our bodies do not store alcohol directly (though a few % may be converted via DNL into fat). Alcohol is burned immediately for current energy needs. Carbohydrate oxidation is labeled "excellent," because when carbohydrate intake increases, the body quickly adjusts oxidation so it burns less fat, and more glycogen, for fuel. Protein is only considered "good," because large increases in protein intake only cause small increases in oxidation. Fat is low man on the totem pole, as it is the reserve fuel. The body is designed to oxidize the other three macronutrients first, so any increase in the oxidation rate of the favored three directly reduces fat oxidation.
Efficient Protein Utilization: The Secret Weapon Of MNP
First, some relevant quotes from metabolism science:
Variation in the apparent sensitivity of the insulin-mediated inhibition of proteolysis to amino acid supply determines the efficiency of protein utilization. Clin Sci (Lond). 1998 Dec;95(6):725-33.
"In other words, dietary carbohydrate is required for an optimal utilization of dietary proteins."
Dietary Carbohydrate Deprivation Increases 24-Hour Nitrogen Excretion without Affecting Postabsorptive Hepatic or Whole Body Protein Metabolism in Healthy Men. J Clin Endocrinol Metab. 2003 Aug;88(8):3801-5.
In plain terms, as carbohydrate intake increases so does the percentage of ingested protein that gets shuttled into muscle stores. For example, the study cited directly above used 3 isocaloric diets containing the same level of protein. Thus the effects of the ratio of carbohydrate to fat could be isolated.
PRO/FAT/CHO % PRO excretion (g/24-h)* insulin** CHO g net PRO g/%PRO***
15/83/2 .............95.6 ...............Low ...........13 g ..................0 ..... 0
15/41/44 ........... 75.6 ...............Med ...........280 g ............19.4 ... 20
15/0/85 ..............67.5 ..............High ..........540 g .............28.1 ...29
*Data from Fig. 2, converting urinary Nitrogen excretion to protein excretion.
**Insulin response from Fig. 1.
***Net 24h protein deposition (intake - excretion) and protein efficiency (% of dietary protein deposited)
The diets provided identical energy (15 kcal/lb) and protein. Thus the results clearly show the superiority of carbohydrates over fat for body recomposition. First of all, notice that the low-carb diet created a low insulin response, which lead to zero net gain of muscle over 24h. Protein requires a large insulin response to push it into storage. Thus, when the mixed diet raised carbohydrate intake to 280g, the insulin response was higher, therefore subjects gained 19 grams of protein (~95 g LBM=1/5 lb of muscle) over 24h, with 20% efficiency (19.4/95.6). Finally, the zero fat, 85% carbohydrate diet (540g) had the highest insulin response, which inevitably forced more protein into storage. Thus the net gain of protein was 28.1 g/95.6, an efficiency of 29% (28g of protein translates to nearly 1/3 lb of LBM). And remember, this is at maintenance (15 kcal/lb). Forget the specific numbers, the lesson here is that if you want to achieve Maximum Nutrient Partitioning, the key is a diet very high in carbohydrates, and very low in fat. The more you step on the carbohydrate accelerator, the stronger the insulin response, and the more protein from the diet is deposited into storage (indeed some starch overfeeding studies have achieved efficiency as high as 66%, with over 60g out of 90g of dietary protein deposited per 24h).
Let's move on to another example:
Metabolic effects of a mixed and a high-carbohydrate low-fat diet in man, measured over 24 h in a respiration chamber. Br J Nutr. 1982 Jan;47(1):33-43.
This classic study compared a mixed diet versus a MNP diet. Once again, protein was kept the same (88g/24h), allowing the ratio of carbohydrates versus fat to show its effect. As part of the study, subjects spent 24h in a respiration chamber (calorimetry is very accurate for measuring oxidation rates). They also cycled for 2.5 hours on a "bicycle ergometer," so the additive effect of exercise could be seen. Here are the startling results from Tables 2 and 3:Diet kcal deficit PRO/FAT/CHO (g) PRO O* (g/24-h) net PRO g/%PRO
MD ....... -339 ........88/85/228 ............77 .................+11 ....13
HCLFD ...-456 ........88/9.5/406 ...........71 .................+17... 19
*Protein oxidation.
Notice what happens when exercise is combined with a low-kcal MNP diet. Both groups were in negative energy balance due to the addition of cycling. Yet despite a significantly greater net energy deficit (-456 Vs. -339), the HCLFD deposited 55% more net protein into storage compared to the MD (+17 Vs. +11). These data elucidate the lopsided power of carbohydrate versus fat when it comes to protein efficiency: while 19% of ingested protein made it to storage for the HCLFD, only 13% was stored by the MD, despite the fact that the MD group was over 120 kcal closer to meeting energy needs! In terms of body recomposition for the 24h period, both diets were successful. The MD increased LBM by about 55 grams, while reducing fat stores by 75 g. The HCLFD increased LBM by about 85 grams, while reducing fat stores by 80.5 grams (Table 3). Yet the HCLFD clearly outperformed the MD, causing more net muscle gain and more net fat loss, despite a greater net energy deficit! Such is the power of increasing the ratio of CHO:FAT in diet.
Confirming these results is the superb study by Horton et al., which compares the different effects of carbohydrate and fat overfeeding. If you want a deeper understanding of these issues, click on the citation below to download and study the full .pdf file. In this study carbohydrate overfeeding achieved much better body recomposition results compared to fat overfeeding, and how could it not, human metabolism and physics make it the inevitable result.
In 2002, Rozenek et al. published a study confirming that carbohydrate overfeeding combined with weight training created a better recomposition result than an isocaloric diet higher in total protein.
Both groups trained 4 d/wk for 8 weeks, with each session lasting between 60-90 minutes. Each group, in additional to their regular diets, ingested a daily supplement containing 2010 kcal (a control group did not get the supplement). The high protein group received an extra 356g CHO, 106g PRO, 18g FAT. The high carbohydrate group received an extra 450g CHO, 24g PRO, 14g FAT.
Here are the results from Table II:
......Group 1 (CHO/PRO)..Group 2 (CHO) ..Group 3 (CTRL)
Fat gain/loss ..+200g (.4 lb)...-300g (-.7 lbs) ....-800g (1.8 lbs)
LBM gain ....+2.9 kg (6.4 lbs)...+3.4 kg (7.5 lbs) +1.4 (3.1 lbs)
Once again the metabolic consequences of higher carbohydrate, lower fat diets is confirmed: the CHO group actually lost .7 lbs of fat while gaining 7.5 lbs of muscle! The CHO/PRO group gained .4 lbs of fat and 6.4 lbs of muscle. Clearly, overfeeding combined with exercise gave both supplemented groups excellent body recomposition results, yet the best results were in the CHO group. Since the unsupplemented diets were typical (high in fat), the results would have been even more striking if the ratio of carbohydrates to fat was shifted further towards optimal protein efficiency (MNP).
50-100 Grams Of Protein A Day Is Enough For MNP
By understanding the way basic physics and human metabolism intersect to produce body composition, Maximum Nutrient Partitioning can be achieved. The most efficient pathway towards maximizing muscle and minimizing fat is the MNP diet. Don't believe the hype - bucketloads of protein are not necessary, and as demonstrated by the studies I've cited, protein intake greater than 90-100g/d is not necessary for large muscle gains, and in fact can be counter productive.
The Three Main Factors Of MNP
Through examining well-designed studies, the basics of optimal body recomposition are brought into the light:
#1 Step on the carbohydrate accelerator.
Eat a diet very high in CHO, very low in FAT, and moderate in PRO. Carbohydrates will directly stimulate insulin, which will push both protein and fat into storage. Yet since FAT intake is strictly controlled, net muscle gain will be achieved with minimal fat gain.
#2 Further shift metabolism towards MNP with exercise.
Exercise stimulates energy expenditure (FAT/CHO oxidation) and significantly increases protein synthesis (for up to 48 hours). When you combine the MNP diet with exercise, you are working with millions of years of evolution to help sculpt your ideal body.
#3 Keep basic physics in mind.
Although one can gain muscle and lose fat at the same time using MNP, the power of MNP becomes more obvious as surplus kcal accumulate. When consuming significantly more kcal than expending, protein stores grow quickly. What the classic bodybuilding mantra of "eat big, lift big" is missing is the strong effect of the macronutrient ratio in the diet. Extrapolating from starch overfeeding studies, it appears that combining MNP overfeeding (1000-1500 kcal above maintenance) with fat-burning exercise will put on 1/2-3/4 lb of LBM per day, with zero fat gain! Although total kcal intake is the biggest factor in overall weight gain, the macronutrient ratio of a diet also has a profound effect on body composition. Most overfeeding studies use a high fat diet, so the weight gained tends to have a high ratio of FAT to PRO. So for every 1 gram of net protein gained, they also gain 8-14 grams of FAT. But studies that keep FAT below 20% deposit much less fat. So for every 1 gram of protein, they gain only 1-4 grams of FAT. But the MNP diet is even lower in FAT: 5-10%, so the results are even better. For more detail about the practical details of the ultimate body recomposition plan check out MNP 100% Muscle.
More To Come
Minor MNP factors will be covered in future posts (complex carbohydrates versus simple sugars, alcohol, fasting, speed of digestion/gastric emptying/satiety signals, high intensity versus low intensity). Thank you for reading; feel free to ask questions. By implementing Maximum Nutrient Partitioning daily (in addition to exercise), you are choosing to follow most direct pathway to a more muscular and less fat you. You get the most bang for your metabolic buck. You get Maximum Nutrient Partitioning.
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