Glycative Stress Research
Online edition : ISSN 2188-3610
Print edition : ISSN 2188-3602
Received : November 29, 2017
Accepted : January 10, 2018
Published online : March 31, 2018

Review article

Consideration of adequate carbohydrate intake
Satoru Yamada
Kitasato Institute Hospital Diabetes Center, Tokyo, Japan.

Abstract

The conventional wisdom of nutritional science for the last 40 years has radically reversed. In the past, it was consideredthat fat intake was suspected to be the cause of cardiovascular diseases, and the intake of protein to be the cause of thedeterioration of renal function, so it was recommended to minimize their intake and make up the lack of energy with theintake of carbohydrates. However, today, there is no such concept in present nutritional science.
Meanwhile, the results of research in low carbohydrate diets were accumulated worldwide and it was shown that a dietwith 120 g, or less than 150 g, of carbohydrates a day is effective in all components of metabolic syndrome such as blood
glucose, body weight, blood pressure and lipid profile. Randomized control trials of low carbohydrate diets have been reported
in Japan, which show the effectiveness of moderate low carbohydrate diets.
A low carbohydrate diet is assumed to have a great effect not only on metabolic syndromes, but also various diseases
and clinical conditions such as dementia, locomotive syndrome (sarcopenia and frailty) and the appearance of aging. A low
carbohydrate diet is also presumed to maintain and improve the functions of internal organs by inhibiting the glycation ofproteins in each organ associated with the intake of carbohydrates.
In terms of the quality of carbohydrates, papers supporting diets consuming food with low Glycemic Index (GI) havebeen reported. Furthermore, papers supporting the style of eating called “eating order diet taking carbohydrates last” havealso been reported.
It is desirable that many people recognize and practice appropriate methods of carbohydrate intake from the viewpointsof quantity, quality and order, and the concept of “enjoying tasteful meals and good health” will become a reality.

KEY WORDS: obesity, diabetes mellitus, metabolic syndrome, nutrition therapy and low-carbohydrate diet (Locabo)

1 Introduction

methods of carbohydrate intake as a diet preventing transient
postprandial hyperglycemia and glycative stress following
meals, as well as express our opinions on this topic.

Monnier et al. revealed more than 10 years ago that blood
glucose fluctuation positively correlates with oxidative stress 1).
Since then, it has become known that the amount of fluctuationin blood glucose level correlates with reduced cognitive
performance 2). Transient postprandial hyperglycemia, called a“glucose spike,” is associated with organ disorder at the samelevel or more as stable hyperglycemia. At one time, it wasconsidered that it takes more than certain hours to produce
advanced glycation end products (AGEs) caused by being
exposed to high blood glucose levels. However, recently it
has become known that the production of AGEs occurs in ashort time 3). In other words, the problems of glycative stresscaused by this transient hyperglycemia became known. In
this review, we will give an outline of the great changes innutritional science at present, as well as discuss appropriate

Correspondence to: Satoru Yamada MD, PhD
Kitasato Institute Hospital Diabetes Center
5-9-1 Shirokane, Minato-ku, Tokyo 108- 0072, Japan
Tel: +81-3 -3444 - 6161
eMail: Yamada-s@insti.kitasato-u.ac.jp

2 Great Change in Nutritional Science

In order to discuss the appropriate intake of carbohydrates,
it is important to know that nutritional science is in a periodof great change at present. In 2015, the Dietary Guidelines
Advisory Committee in the USA released a report statingthat “Reducing total fat does not lower cardiovasculardisease (CVD) risk” and “Limiting total fat was also notrecommended for obesity prevention.” The committee also
reversed nearly 4 decades of nutrition policy and raised theupper limit on the recommended amount of fat intake 4).

_ 1 _Glycative Stress Research 2018; 5 (1): 001-011(c) Society for Glycative Stress ResearchAdequate Carbohydrate Intake
the American Diabetes Association had said “The single
most important objective in dietary treatment of diabetic
patients is the control of total caloric intake to attain an ideal
body weight” 8). However, in 1994, the Association excluded
it from the most important tasks, saying “Traditional dietary
strategies, and even very-low-calorie diets, have usually not
been effective in achieving long-term weight loss” 9).
In other words, all of the following items that had been
recommended until several years ago were no longer thought
to be effective; (1) low-energy diet (moderate eating) is goodfor health ( denied because it cannot be maintained in
the long term), (2) low-fat diet is effective in the preventionof CVD ( denied because it is not effective) and (3) lowprotein diet is effective in the protection of renal function( denied because it is not effective). Furthermore, (4) lowcarbohydrate diet, an item that had been denied until several
years ago, became recommended as the first choice.
In order to consider the method of appropriate
carbohydrate intake, it is extremely important to understand
why a low-energy diet, low-fat diet and low-protein diet that
had been regarded as effective were denied, so these diets are
explained in detail as follows.

These changes in nutritional policies were not something
the Dietary Guidelines Advisory Committee in the USA
suddenly came up with. For example, “Eat Butter” washeadlined on the cover of the Time magazine June 23, 2014
issue. Compared with the article “Hold eggs and butter”
posted in the magazine’s March 26, 1984 issue, the way of
thinking about fat intake (the lipid in this case is saturated
fatty acid, which is often considered to be animal fat) was
clearly reversed in 2014 (Fig. 1).
The thinking regarding carbohydrate intake also
was clearly reversed. In 2006, the American Diabetes
Association (ADA) declared “ Low- carbohydrate diets are
not recommended (which means the Association cannot
recommend it )” 5). However, it changed their description to“For weight loss, either low-carbohydrate or low-fat calorierestricted diets may be effective” 6), and finally in 2013, it
recommended low carbohydrate diets, saying “prescribeddiabetic eating patterns have been shown to be moderately
effective in managing diabetes, including Mediterraneanstyle diets and lower-carbohydrate patterns” 7). It is clear
from the changes in these descriptions that their thinking had
been gradually changed. In short, they said that they could
not recommend low carbohydrate diet but they recommended
it only seven years later (from 2006 to 2013).
Furthermore, their way of thinking about protein has
also been reversed. The American Diabetes Association
had insisted that a reduction of protein intake may improvemeasures of renal function” until 2008 6). However, in 2013,it said “Reducing the amount of dietary protein is notrecommended because it does not alter the course of GFRdecline” 7).
Although, even now in Japan, a low-energy diet is
accepted as the only dietary method for the treatment ofdiabetes, and it is handled differently in the USA. Since thetime when it prepared its first Nutritional Guidelines in 1971,

→

→

→

(1) Low-energy diet

A low-energy diet has played a central role for a longtime as diet therapy for anti-aging therapy and the treatment
of diabetes.
Actually, a low-energy diet has shown life-extending
effects in experiments with various animal species. An
experiment with rhesus monkeys conducted by the Universityof Wisconsin showed not only that a low-energy dietsignificantly reduced age-related deaths, but also that it
prevented the onset of diabetes, CVD, cancer and dementia 10).
Therefore, the same effects in humans were expected. In

a. 1984

b. 2014

Fig. 1. Front page of the journal “ TIME”.

The difference between blue color “Hold the eggs and butter” in 1984 and block color “Eat butter” in 2014 shows a paradigm
shift in nutrition. a. “Cholesterol”, Mar 26, 1984; Vol. 123, No. 13. b. “Ending the War on Fat”, June 23, 2014; Vol. 183, No. 24.

_ 2 _Glycative Stress Researchother words, a low-energy diet had played the most importantrole in the prevention and treatment of metabolic syndrome(clinical conditions where CVDs are easily caused by the
integration of blood glucose abnormality, blood pressure
abnormality and lipid profile abnormality based on theaccumulation of visceral fat) for a long time. However,in the Look AHEAD trial where diabetic patients wereadministered a low-energy diet, a reduction in total mortality
and a decrease of CV events were not recognized, and thebone mineral density (BMD) of male’s femoral neck weresignificantly reduced compared with that of the control
group 11). The deterioration of bone metabolism like thisalso was recognized in the rhesus monkeys mentioned
previously 12). Furthermore, the life-extending effects ofa low-energy diet were not recognized in the experimentwith monkeys conducted by the National Institute of Aging(NIA) in the USA 13). In addition, according to a recently
reported CALERIE trial, problems in reduction of BMD,
decrease in muscle mass, and treatment-resistant anemia
occurred in healthy subjects who were guided to restrict
their energy intake to 75% of their previous intake 14-16). In
other words, we have had to recognize that a low-energy dietpossibly accelerates locomotive syndrome (clinical conditions
tending to become bed-ridden caused by osteoporosis, joint
degeneration and muscle atrophy), far from a solution for
metabolic syndrome.
It is known that if the actual energy intake is presumed
to be 100, the energy recorded personally as consumed isaround 15-25% less than 100 17, 18). The more overweightthe person is, the smaller this figure becomes. For example,
in the case of an obese person with a body mass index(BMI) greater than 30, this figure decreases to around 70 19).
Therefore, energy restriction has a problem from a realistic
standpoint.
Even in Europe and the United States where almost
100% of the cases of type2 diabetes develop through obesity
as previously mentioned, since the end of the 20th century,
the optimization of energy intake has no longer remained
an important task because of the difficulty in maintaining
the effect 9). Even in Japan, where the development of type2
diabetes is not always related to obesity 20), a low-energy diet
only is not enough as an effective diabetes countermeasure,
so it must be reviewed.

cardiovascular mortality or all-cause mortality 23, 24).
On the contrary, the results of the research that fish oil
supplements (ω-3 polyunsaturated fatty acids) can prevent
cardiovascular death and all-cause mortality was reported in
the beginning of this century 25), and, furthermore, that it canalso prevent cardiovascular events by adding plant oil (nuts
30 g/day or extra virgin olive oil 1 L/week) was reported 26).
As a result, the concept that the restriction of fat is not needed
took root. There are several research results from Australia 27)
and the USA 28) that show cardiovascular events and mortality
increase by changing animal fat (saturated fatty acid) toplant oil. There are several reports that in the case of theJapanese, in particular, the larger the intake of saturated
fatty acid, the more they are protected from the onset ofstroke 29-31). Therefore, it seems not to be necessary to also
avoid saturated fatty acids.
According to the PURE Study 32) which was reported
recently, in an observation study of 18 countries on fivecontinents, the more fat a group consumes, the lower its allcause mortality is. Therefore, no one could express the medicalsignificance of low-fat diet in the level of a randomized control
trial or observational study level any longer.
Therefore, at present, the lipids that should be avoided
are old and damaged ones (lipid peroxide) and artificial lipids(trans-fatty acids) only.

(3) Low-protein diet

It has been reported that protein load has renal toxicity
since 1919 33) and the load from a high protein diet had shown
renal toxicity in various experiments with animals until the
1980s, so that the concept of the treatment of renal failure
by low protein diet was established 34). Furthermore, inhumans, according to Nurses’ Health Study, no relationshipbetween the amount of protein intake and the worsening of
renal function (lowering of estimated glomerular filtration
rate: eGFR) after intake was observed in the group without
renal failure (eGFR > 80 mL/min). However, the speed of theworsening of renal function (lowering of eGFR) was fasterin the group with the largest protein intake among the groupwith renal function damaged to a certain extent (80mL/min >eGFR > 50 mL/min); as a result, the hypothesis that protein
intake worsens renal function and low protein diet protects
renal function prevailed 35).
However, no significant protective effect of the low-protein
diet on renal function was recognized, not only in the persons
with normal renal function, but also in those with impaired
renal function in the MDRD Study trying to confirm theeffectiveness of a low protein diet by randomized control trialthat can exclude bias and confounding factors 36). Following
up after that, it was reported that mortality significantly rosewith a strict low-protein diet 37).
After this follow-up of the MDRD Study was reported,
the American Diabetes Association came to deny theeffectiveness of a low protein diet for the protection of renal
function in their nutrition recommendations 7).

(2) Low-fat diet

The Seven Countries Study that was reported in 1953
investigating the relationship between fat intake ratio andcardiovascular motility in the USA, Canada, Australia,
England, Wales, Italy and Japan clarified that cardiovascularmortality is higher in countries where the fat intake ratio ishigh 21). Epidemiological data (observational study) like thishold bias and confounding factors, so that it is clear that
correlation does not imply causation. The concept, whether
there is causation or not in observational studies, had not
sufficiently prevailed prior to 1991, when it was finallyadvocated for evidence-based medicine. Therefore, theconcept that a reduction of fat intake leads to the preventionof cardiovascular death blindly prevailed.
However, after the turn of this century, as the results ofa systematic review of a randomized controlled trial (RCT),in research designed to approach the causation, it was notconfirmed that a low-fat diet supported the improvement ofblood glucose 22), and it was confirmed though meta-analysis
of RCT that a low-fat diet did not support the reduction of

3 Appropriate Amount of Carbohydrate of
Nutritional Science in the Past

It has been generally considered that the threemacronutrients consisting of the ratios of carbohydrate 5065%, protein 13-20% and fat 20-30% (or 25%) to total_ 3 _Adequate Carbohydrate Intake
situation, a low-carbohydrate diet is being reconsidered fromthe viewpoint of its intake volume. The low-carbohydrate
diet that prevailed as a treatment method for lifestyle-relateddiseases in the 20th century, similar to folk medicine, wascompletely discredited 39). The reasons for the criticism
are insufficient scientific grounds and the increase in
cardiovascular risk caused by excess fat intake. It has
become clearly verified that a low-fat diet does not decrease
cardiovascular risk and the scientific grounds for lowcarbohydrate diets have accumulated, and as a result, these
criticisms disappeared.
In the first place, only carbohydrates cause postprandial
hyperglycemia except in the case of type1 diabetes, and it is
known that the intake of protein, fat and dietary fiber reduce
postprandial hyperglycemia ( Fig. 2 ) 40-42). In other words,
diets restricting carbohydrate intake and increasing theintakes of protein, fat and dietary fiber can more effectively
adjust postprandial hyperglycemia and prevent glycative
stress.
A low-carbohydrate diet is expected to reduce theoccurrence of glycative stress 43), reduce oxidative stress 44)
and acquire an anti-aging effect (extending longevity andhealthspan) 45). The medical merits that can be gained fromit are anti-aging effects on the changes associated with aging
including cardiovascular events, cognitive impairment, theloss of skin suppleness (formation of wrinkles) and bonedegeneration. Actually, it is shown that the appearances ofaging in twins are greatly defined by wrinkles of the skin,energy are good for health 38). There are many pieces ofliterature stating that this amount (ratio) of carbohydrates
is appropriate, even now. However, these ratios are only
hypothetically calculated as follows; calculate energy
requirement by multiplying basal metabolic rate by physicalactivity coefficient, set a minimum (or a little more) required
protein from essential amino acids, set a minimum (or a littlemore) required fat amount from essential fatty acids, andfill the rest with carbohydrates. As stated above, a paradigm
shift occurred in nutritional science. In the present situation
regarding nutritional science, it is not necessary to set an
upper limit on fat intake, and it is not considered that renal
dysfunction is caused by protein intake, so we have to saythat the above three macronutrient ratios are meaningless.
Ideal ratios for the three macronutrients are unknown atpresent, so that should be established from now on 7).

4. Appropriate Carbohydrate Intake to be
Considered in terms of Volume

The method to calculate the amount of carbohydrate
intake by setting total energy amount, reducing minimum
required amounts (or a little more) of protein and fat, andobtaining carbohydrates is meaningless when the negative
effect of protein intake on renal function and the promoting
effect of fat intake on arterial sclerosis are denied. In thisDietS

＊ p < 0.05 ( vs SM )45

† p < 0.05 ( vs SMF )

36

SM
SMF
SMFV

Glucose (mg/dL)

27
18

＊

9
0

†

-9
- 18
0

30

60

90

120

150

18 0

Time (min)S dietS

Steamed rice 200 g

338 kcalSM dietS+M

Steamed rice 200 g + Tofu + Boiled egg

486 kcalSMF diet

S+M+F

Steamed rice 200 g + Tofu + Boiled egg +573 kcalMayonnaise

SMFV diet S + M + F + V

Steamed rice 200 g + Tofu + Boiled egg +604 kcalMayonnaise + Spinach & Broccoli

Fig. 2. Plasma glucose change after 4 types of foods.

S, staple food; M, main dish; F, fat; V, vegetable; Tofu, soy bean curd. * p < 0.05 vs. SM diet,† < 0.05 vs. SMF diet. The figure is quoted from Reference 41).

_ 4 _

Glycative Stress Researchand the appearance of aging has strong correlations withmortality and cognitive function afterwards 46, 47). In otherwords, the inhibition of glycative stress and oxidative stressof the whole body due to a low-carbohydrate diet has merits
not only for the prevention and treatment of metabolic
syndrome, but also for the prevention of locomotive
syndrome.
The A to Z Study 48) and the DIRECT Study 49) boosted
the position of the low-carbohydrate diet to be the first
choice of treatment for obesity or diabetes worldwide. The
low-carbohydrate diet employed in these studies was the
Atkins diet. It is a diet that restricts carbohydrates to 20 g/
day in the early period and later changes to a moderate
restriction of up to 120 g/day.
The A to Z Study 48) is a randomized control trial targeting
American patients with obesity. Four types of diets (1) Atkins
diet, (2) traditional diet (low fat and low energy diet), (3)Ornish diet (a substyle of vegetarianism) and Zone diet(proportions of carbohydrate, fat and protein are 40:30:30)
were compared. The low-carbohydrate diet group (Atkins
diet group) achieved the best effects in the change of bodyweight and the improvements of lipid profile and bloodpressure (Fig. 3).
The DIRECT Study is a randomized control trial
targeting 322 patients with abnormal body weight (BMI 27
or more) working in one facility in Israel. The following three
diets were compared; (1) Low-carbohydrate diet (Atkinsdiet), (2) Mediterranean diet (energy intake of 1,800 kcal formales and 1,500 kcal for females, with less meat and a highvolume of fish, vegetables, and lipids, mainly by olive oil,
up to an energy ratio of 35%) and (3) a low fat diet (energy
is 1,800 kcal for male and 1,500 kcal for female with a lipid
ratio of less than 30%). Although all groups successfully
lost weigh over two years, the low-carbohydrate diet groupresulted in the best effect ( Fig. 4 ) 49). Low-carbohydrate
diet resulted in the best improvement in lipid profile,high sensitivity C-reactive protein (hsCRP), adiponectinand HbAlc 49). In the sub-analysis that followed, the lowcarbohydrate diet improved eGFR 50) and carotid intimamedia thickness 51) and its effects on weight loss and lipid
profile improvements were maintained for 6 years 52).
While the reports of the randomized control trials for

Zone

LEARN

the low-carbohydrate diet shown above were accumulated,
the reports in which Santos et al. meta-analyzed 17 piecesof data showed that a low-carbohydrate diet significantly
improved the control of blood glucose, lipid profile, bodyweight, blood pressure and hsCRP. It was also shown that the
low-carbohydrate diet is very appropriate as a therapeutic
diet for metabolic syndrome and diabetes ( Table 1 ) 53).
We released a report on a randomized control trial
targeting the Japanese for the first time 54). Type 2 diabetic
patients were randomly assigned to (1) a moderately lowcarbohydrate diet or (2) low-energy diet. In this research,diet was restricted to more than 20 g and less than 40 g
per meal, and not less than 120 g a day. It inhibited blood
glucose spikes after meals. They were encouraged to takesnacks with carbohydrates of up to 10 g a day (This resulted
in encouraging the intake of carbohydrate 70-130 g/day).
This was for the purpose of ensuring the pleasure of eating.
This moderately low-carbohydrate diet called Locabo
resulted in an improvement in the control of blood glucose
and triglyceride ( Fig. 5 ) 54). In this research, changes inbody weight were not observed. However, as a result of theanalysis of the changes in body weight of 200 subjects who
were instructed with Locabo in another case, the more obese
they were, the more substantially they could achieve weight
loss, there was no change in those with a normal BMI, andthose who had been thin gained body weight (due to increaseof muscles) ( Fig. 6 ) 55).
Another group drew on our research and released areport that the instruction of a low-carbohydrate diet of 130
g/day was superior in the control of blood glucose level andbody weight than a low-energy diet 56).
As described above, there are some differences in thecontents of the low-carbohydrate diets employed in eachclinical trial. However, there is a report that there was nodifference in body weight-loss effect between very lowand moderately low-carbohydrate diets, and the moderately
low-carbohydrate diet maintained a weight loss effect fora longer period (Fig. 7 ) 57). We are employing a moderately
low-carbohydrate diet. Although there is also a report that avery low-carbohydrate diet is superior in the improvementof HbAlc than a moderate one 58), if several outliers are
excluded, there appears to be no difference ( Fig. 8 ).

OrnishAtkinsMean Weight Change (kg)

-0
-1
-2
-3

Fig. 3. Body weight change in 4 typesof dietary intervention in A to Z
study.

-4-5

LEARN, Lifestyle, Exercise, Attitudes,
Relationships and Nutrition; The LEARN
diet is low in fat, is high in carbohydrates.
The figure is quoted from Reference 48).

-6
-7
Baseline2612Time (month)_ 5 _Adequate Carbohydrate Intake-0

Mean Weight Change (kg)

-1
-2
-3
-4
-5
-6
Low-fat diet
Mediterranean dietLow-carbohydrate diet

-7
-8
0

2

4

6

8

10

12

14

16

18

20

22

24

Months of Intervention

Fig. 4. Body weight change in 4 types of dietary intervention in DIRECT trial.

* p < 0.001 for both comparisons with the low-fat diet. The figure is quoted from Reference 49).

Table 1. Results of meta-analysis of RCT in 1,141 obese patients of 17 institutes.

Risk factor

Effect of low-carbohydrate diet

WeightBMI
Abdominal girth
BP (systolic)BP (diastolic)TG
FPG
Glycohemoglobin
Serum IRI
HDL-C

– 7.04 kg(– 7.20 to – 6.88)– 2.09kg/m 2(– 2.15 to – 2.04)– 4.81 mmHg(– 5.33 to – 4.29)– 5.74 cm– 3.10 mmHg(– 6.07 to – 5.41)(– 3.45 to – 2.74)– 29.71 mg/dL(– 31.99 to – 27.44)– 0.21%(– 0.24 to – 0.18)– 1.05 mg/dL– 2.24 μIU/mL

1.73 mg/dL(– 1.60 to – 0.44)(– 2.65 to – 1.82)(1.44 to 2.01)

Parentheses indicate 95% CI. RCT, randomized controlled trial; BMI, body mass index: BP, blood pressure;TG, triglyceride; FPG, fasting plasma glucose; IRI, immune-reactive insulin; HDL-C, high-density
lipoprotein-cholesterol; CI, confidence interval. The data are based on Reference 53).

a. HbA1c (%)

b. TG (mg/dL)

8

180

7.8

160

7.6

140
120

7.4

100

7.2

80

7

60

6.8

40

6.6
6.4

20

0 momth

2 momth

4 momth0

6 momth

0 momth

2 momth

4 momthFig. 5. The changes in HbA1c and TG in Kitasato Institute Hospital Study.
a. HbA1c, b. TG. TG, triglyceride. The figures are quoted from Reference 54).

_ 6 _6 momthGlycative Stress Researcha. Weight Change (%)
6.0

b. HbA1c Change (%)
12.0

6 months
12 months

4.0

6 months
12 months

8.0

2.0

4.0

Obe 1 Obe 2 Obe ≥ 3

Norm

0.0

Low

0.0

Low

- 2.0

- 4.0

- 4.0

- 8.0

- 6.0

- 12.0Norm

Classif icationObe 1 Obe 2 Obe ≥ 3

N

BMI

Low

Low weight（Thin）

<18.5

Norm

Normal weight>= 18.5,

Obe 1

Obesity（Level 1）

>
= 25,

< 30

74

Obe 2

Obesity（Level 2）

>
= 30,

< 35

29

Obe >
=3

Obesity（Level >
= 3）

>
= 35

9
73

< 25

9

Fig. 6. Changes in body weight and HbA1c after Locabo induction.

a. Weight change, b. HbA1c change. Locabo, low-carbohydrate diet; BMI, body mass index. The figures are quoted
from Reference 55).

3.50

2

2.50

HbA1c Change (%)

Change in Body Mass (kg)3.00

Ketogenic low-carbohydrate diet
Moderately low-carbohydrate diet

0
-2
-4
-6

Ketogenic low-carbohydrate diet
Moderately low-carbohydrate diet

-8

2.00
1.50
1.00
0.50
0.00
- 0.50- 10- 12- 1.00

0

1

2

3

4

5

6

- 1.5010

Week of Study- 20.00 - 15.00 - 10.00 - 5.00

0.00

5.00

10.00

Weight Change (kg)Fig. 7. Body weight changes in ketogenic low-carbohydrate
diet and non-ketogenic moderately low-carbohydrate
diet.

Fig. 8. Body weight and HbA1c changes in ketogenic lowcarbohydrate diet and non-ketogenic moderately
low-carbohydrate diet.

Non-ketogenic moderately low-carbohydrate diet;
Ketogenic low-carbohydrate diet. The figure is quoted from
Reference 57).

Non-ketogenic moderately low-carbohydrate diet;
Ketogenic low-carbohydrate diet. The figure is quoted from
Reference 57).

_ 7 _Adequate Carbohydrate Intake

5. Appropriate Carbohydrate Intake to be
Considered in terms of Quality

7. Appropriate Carbohydrate Intake to be
Considered in terms of Consistency

Along with the accumulation of medical evidenceof low-carbohydrate diets controlling the quantity ofcarbohydrates, low glycemic index (GI) controlling the qualityof carbohydrate has drawn attention. This was advocatedby Jenkins et al. of Canada in 1981 59) for the purpose ofcontrolling blood glucose based upon the fact that whendifferent carbohydrates of the same amount were consumed,
the area under the blood glucose rising curve is different
based on the food consumed.
However, because GI is an absolutely average value ofmultiple people, the blood glucose levels of all subjects are
not always inhibited according GI 42). The consumption oflarge amounts of food, even if it is of low GI, raises blood
glucose level by that much.
The Omni Carb Trial is a clinical trial to verify whether
quantity or quality of carbohydrates is more useful for thecontrol of cardiovascular risk, and the results show that thequantity of carbohydrate was found to be more useful 60).
According to the research on the comparison between
a low-carbohydrate diet and a low-energy diet with low GI
food by Westman et al., the low-carbohydrate diet was more
useful than the low energy diet for blood glucose control(improvement of HbA1c), even though it could not be
statistically significant 61).
Furthermore, the direct effect of fructose in raising blood
glucose level is small and its GI is around 20 (it is 100 for
glucose). However, the comparison between the fructose only
group and the glucose only group showed that the impaired
glucose intolerance of the fructose consuming group was
worse after three months. The reason for this is considered tobe that the fatty liver of the fructose consuming group was
more severe, and more visceral fat also was also accumulated.
As a result, their insulin resistance became strong 62). It isconsidered to be that because fructose works in the reward
system of the brain, dependence tends to occur 63).
From the above, the way of thinking to depend upon GI
only cannot inhibit postprandial hyperglycemia, so oxidative
stress and glycation reactions cannot be stopped.
Nevertheless, owing to the aggressive study by BrandMiller et al., it is known that a low GI diet is effective forblood glucose control 64). When it is difficult to control the
intake of carbohydrates by quantity, it will be effective toconsider the quality.

So far it has been shown that postprandial hyperglycemia
can be corrected by focusing on the fact that (1) it is a time ofa great paradigm shift in nutritional science (2) in which lowcarbohydrate diet has been verified to be medically effectiveand (3) low GI diet and eating order diet in addition to a low
carbohydrate diet are also focused on.
However, we consider that a moderately low-carbohydrate
diet (Locabo) is the best way to consume carbohydrates fromthe perspective of the consistency of the Japanese diet.
The definition of Locobo is described here again.
Consume 20-40 g of carbohydrates per meal, and additionallyconsume up to 10 g/day as a snack. As a result, thecarbohydrate intake amount per day is from 70 to 130 g/day.
When advocating Locabo, its slogan is “Enjoy delicious
meals and good health.” More specifically considered, theintake of carbohydrates by the Japanese at present, 260-300
g/day, should be reduced by more than half. According to
the experience in the Kitasato Institute Hospital, the ratiosof carbohydrates and fat and protein of the Locabo diet are
30%, 40-45% and 25-30%, respectively. According to Dietary
Reference Intakes, an appropriate ratio of carbohydrate, fat
and protein is 50-65%, 20-30% and 13-20%, respectively.
As previously mentioned, although there is no medical reason
for these nutrition ratios, due to the Locabo diet, the present
carbohydrate intake of Japanese is halved.
Furthermore, studies on how to decide the ratios of fat
and protein for this low-carbohydrate diet is insufficient.
Prof. Westman of Duke University and other research groupsof Nordic countries prefer a low-carbohydrate and high-fat
diet, and Prof. Ebbeling et al. consider a low-carbohydrate
and high-protein diet to be preferable. We personally consider
that you have to only consume meat, fish and soybean
products regardless of likes or dislikes as to the sources ofprotein intake and to use olive oil, sesame oil and butter asseasoning when necessary without being biased by either alow-carbohydrate and high-fat diet or low-carbohydrate andhigh-protein diet.
I think that the diet called Locabo presumably has merit
to men and women of all ages and it has no demerit. It is notthat the merit cannot be obtained at all if your diet doesn’t
perfectly fall under the definition of Locabo. Because thecarbohydrate restriction and its effect on the improvement ofblood glucose are in linear correlation 67, 68), if the intake of
100 g of carbohydrates per meal is reduced to 60 g, the effectfor that amount can be expected (2/3 of the effect at the time
when it is 40g).
Meanwhile, even if a strict low-carbohydrate diet of lessthan 20 g per meal is practiced, there is no guarantee thatthe merit will increase but it may possibly cause medical
demerits 57). In addition to these medical demerits, a strict
low-carbohydrate diet of less than 20 g per meal limits thekinds of vegetables that can be eaten and it will possibly
reduce the quality of life. We should enjoy happy eating
habits, not being stoic. This is the condition of Locabo
which we consider to be an appropriate method of intake forcarbohydrates.

6. Appropriate Carbohydrate Intake to be
Considered in terms of Eating Order
There is an eating order for the diet to make the bestuse of the actions by proteins, fat and dietary fibers in theinhibition of postprandial hyperglycemia. Although in theearliest years, the importance of eating vegetables first was
advocated 65), and after that it was verified that meat and fish
also have the same effect as vegetables 65), so that it has cometo be recognized that it is important to eat carbohydrates last.
Although enough data have not been collected from a global
standpoint, it may be theoretically correct.

_ 8 _Glycative Stress Research

Meanwhile, there is a report that the amount of glycogenin the muscles and its performance in marathon runners andtriathletes who were practicing carbohydrate restriction were
not different from those of the people who were consuming
a high carbohydrate diet (carbohydrate loading so to speak),so it does not mean carbohydrate intake should be increased
just because the person is doing exercise 71, 72).
It is desirable that many Japanese promote their healthwhile enjoying happy eating habits thanks to the prevalenceof the thinking way of Locabo. We would be happy if thereaders of this paper will participate in this approach.

8. Conclusion

Japanese people consumed large amount of rice
(carbohydrate) in the past but they did not suffer lifestylerelated diseases as they do today. Therefore, a prevalent
way of thinking is that it is not necessary to decreasecarbohydrates. It sounds persuasive to some people. However,
we should remember that Japan had been importing rice until
around 1950 and it was around 1965 when Japan was able
to achieve self-sufficiency in rice 69). Even though Japaneseeating habits were healthy during the 10 years around 1960,
it should not be forgotten that it was under the condition at
the time “when the physical activities of Japanese during 10
years around 1960 could be regained”.
There is a report that the amount of physical activity iscorrelated not only with insulin sensitivity (ability to process
glucose in response to a certain amount of insulin) but also
the insulin secretion ability of the pancreas (ability to secrete
insulin in response to certain blood glucose levels) 70).
Locabo is an appropriate carbohydrate intake method
for most Japanese people at present. However, those whowant to consume more carbohydrates will be able to enhance
the ability to process carbohydrates and appropriately
consume more carbohydrate by increasing their physicalactivities and building their muscle mass.

Conflict of interest

The authors declare no conflict of interest in this study.

Acknowledgement

The outline of this study was presented at the 12th
meeting of Society for Glycative Stress Research (May 26,
2017, Tokyo),

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