Page 71 - GTM-2-1

Global Translational Medicine Mass balance

Where Daily Net Fat Oxidation is another estimate factor of body mass and fat mass loss. It just happens
calculated by simultaneously with decreased nutrient mass intake. What
Daily Net Fat Oxidation = 1.63VO – 1.64VCO – 1.84N about de novo lipogenesis (DNL), that is, the process
2 2 of synthesizing fatty acids from acetyl‐CoA subunits?
(2)
Hyperinsulinemia, caused by the consumption of a large
Where VO and VCO are the volume (in L) of amount of carbohydrates, can increase DNL, but it is only
2
2
consumed O and produced CO , respectively, while N is relevant in extreme overfeeding situations. DNL seems to
2
2
the urinary nitrogen excretion per 24 h. In these equations, play a central role in the pathogenesis of non-alcoholic
the only precise numeric input is Daily Fat Intake, fatty liver disease but this topic is beyond the scope of
[15]
whereas Daily Net Fat Oxidation is an estimate obtained this article.
from estimates that inevitably increase the inaccuracy of However, insulin levels can be important in terms of
measurement. As recently discussed by Arencibia-Albite , where body fat is reduced. Since high insulin levels favor
[1]
the aforementioned equations overlook, among other fat synthesis and inhibit lipolysis, it seems reasonable
things, the fact that body fat can also decrease through the that the reduction of body fat occurs primarily through a
excretion of fatty acid derivatives. reduction in dietary fat intake during a high-carbohydrate
7. A low-carbohydrate diet provides diet. In contrast, a low-carbohydrate diet lowers insulin
less nutrient mass than an isocaloric levels, thus reducing fat synthesis and stimulating lipolysis,
which nullify the effects of high dietary fat intake. These
high-carbohydrate diet factors may explain why low-carbohydrate diets tend to
A low-carbohydrate/high-fat diet leads to a greater work well for visceral fat reduction [16-18] .
body mass and fat mass loss than an isocaloric high- Goss et al. have recently reported that the very-
carbohydrate/low-fat diet (LFD) because it provides less low-carbohydrate/high-fat diet group in their 8-week
nutrient mass [1,3,7,8] . When the energy fraction from dietary study experienced a 3-fold greater loss of visceral
fat increases, while energy intake is clamped (i.e., fixed), adipose tissue (VAT) and intermuscular adipose tissue
mass intake decreases due to the significantly higher energy (IMAT) when compared to the high-carbohydrate/LFD
density of fat compared with other energy substrates. Such group . Following a very-low-carbohydrate/high-fat
[17]
a difference in mass intake translates into greater body mass diet, there was a significantly greater decrease in fasting
and fat loss in a low-carbohydrate diet versus an isocaloric insulin level compared to the high-carbohydrate/LFD
high-carbohydrate diet. If such a feeding response is not (13.7 ± 5.6 → 9.4 ± 4.0 vs. 15.6 ± 6.5 → 16.0 ± 8.2) µU/mL. It
observed, then it is simply not a well-controlled study, as should be noted, however, that the very-low-carbohydrate/
alternative results would indicate a violation of the Law of high-fat group consumed significantly lesser total
Conversation of Mass. calories, and thus nutrient mass, per day than the high-
If two persons eliminate body mass at the same daily carbohydrate/low-fat group. Nevertheless, it seems that
rate, then the one ingesting less nutrient mass will express the very-low-carbohydrate/high-fat diet works particularly
a greater daily body mass and fat loss. For instance, the well on these metabolically harmful fat depots.
daily energy intake of 2,500 kcal distributed as 30% fat Figure 2, which is adapted from Arencibia-Albite’s and
(9.4 kcal/g), 55% carbohydrate (4.2 kcal/g), and 15% Manninen’s study , presents two hypothetical overweight
[7]
protein (4.7 kcal/g) corresponds to a mass intake of ~487 g, individuals whose body composition and total energy
whereas the same energy intake distributed as 60% fat, 30% intake were identical but macronutrient distribution was
carbohydrate, and 10% protein reduces mass ingestion by clearly different.
~96 g. This is not a small difference in the long run.
8. A highly controlled metabolic ward
It has been suggested that a low-carbohydrate diet is feeding trial supporting the mass balance
more effective than an isocaloric high-carbohydrate diet
in losing body mass and fat mass because the former approach
lowers insulin levels . However, it is worth noting that When it comes to proving causality in this matter,
[14]
insulin or any other hormones cannot create any kind metabolic ward studies are considered the gold standard.
of mass out of thin air. Only ingested nutrient mass can Unfortunately, the cost of implementing such trials makes
result in increased body mass. Insulin just ensures that it unlikely that any new ones will be conducted in the
this mass can be stored. Similarly, lowered insulin levels near future . As of now, the best controlled experiment
[19]
cannot magically destroy any mass. Although insulin levels performed in a metabolic ward is that of Hall et al. . The
[11]
decrease with a low-carbohydrate diet, it is not a causal results of the study are in full agreement with the mass

Volume 2 Issue 1 (2023) 7 https://doi.org/10.36922/gtm.222