J Rehabil Health Sci 2010; 8: 1-7Ⓒ 2010 Osaka Prefecture University

Review

Eating Order Diet Reduced the Postprandial Glucose and Glycated Hemoglobin Levels
in Japanese Patients with Type 2 Diabetes
Saeko IMAI†１ and Shizuo KAJIYAMA２,３
１

Department of Clinical Nutrition, Faculty of Comprehensive Rehabilitation, Osaka Prefecture University, Osaka, Japan ; ２Kajiyama
Clinic, Japan ; ３Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of
Medical Science, Japan
Received September 2, 2010 ; accepted September 29, 2010
Key words : type 2 diabetes; dietary interventions; glycemic control; vegetables; carbohydrate

1 Postprandial hyperglycemia is associated withincreased risk for macrovascular diseases
It is important to manage good metabolic control inpatients with diabetes in order to prevent chronic
complications. 1,2 However, a significant number ofpatients with diabetes remain poorly controlled, mainly asa result of low compliance of diet. 3-5 The important
choices that affect blood glucose control in people withdiabetes are made by themselves, and not by their
physicians or other medical professionals. People withdiabetes are advised to adopt an appropriate dietincluding dietary habits and meal patterns on a lifelong
basis. Frequently, the efforts of patients are not in theappropriate directions, or they may receive confusing andcontradictory advice from the media or social contacts.
Diabetes education, especially dietary education, requires
training by medical professionals and provision ofunequivocal information. Traditionally, recognition of
the relationship between dietary constituents and glucose
tolerance has contributed to the development of
nutritional prescriptions. Such strategies aim to restrict
energy intake and provide macronutrient balance.
However, diabetic patients may have trouble
understanding diets based on a restrict energy intake, andeven if they do understand the system, they may havedifficulty changing their daily food habits.3 In particular,
elderly diabetic patients may experience difficulties
implementing the recommendations of the restrict energy
intake.
It has been demonstrated that postprandial
hyperglycemia is associated with increased risk formacrovascular diseases.6 The recommendations of theInternational Diabetes Federation in 2007 were intended†

Corresponding author. E-mail: poooch@rehab.osakafu-u.ac.jp

to assist in developing strategies to effectively manage
postprandial glucose levels in people with diabetes.
Strategies for nutritional education should be reorganized to provide a simple and easy meal plan thatlowers postprandial hyperglycemia in patients withdiabetes.
First, we reported an acute study of eating‘vegetables before carbohydrate’ on postprandial glucose
and insulin levels in patients with type 2 diabetes mellitus(T2DM). Second, we analyzed the retrospective study todetermine whether educating diabetic patients to eat‘vegetables before carbohydrate’ was effective on longterm glycemic control.
2 Crossover study of the effect of ‘vegetables before
carbohydrate’ on the postprandial glucose andinsulin levels in Japanese patients with type 2
diabetes mellitus7
We conducted a randomized crossover study insubjects with T2DM. We recruited 15 patients (7 men
and 8 women), enrolled from outpatients with T2DM
controlled by diet in Kajiyama Clinic specializing in the
diabetes treatments. The exclusion criteria were as
follows: (1) mean hemoglobin A1c (HbA1c) level in thepast 6 months > 6.9% (2) chronic liver disease or aclinical history and/or signs of cardiovascular disease,cerebrovascular disease, or peripheral arterial disease (3)heavy smoking (more than 40 cigarettes a day), anddrinking (more than 50 g alcohol a day); (4) and use ofany dietary supplement in the 2 months before the start ofthe study. No change was made to therapy during thestudy.
Their clinical characteristics were as follow, mean ±SD; age 61.7 ± 11.6 yrs, BMI 24.7 ± 4.3 kg/m2, HbA1c
6.0 ± 0.6%, duration of T2DM 5.3 ± 8.8 yrs. A test meal,

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consisted of white rice and vegetable salad of sliced
cabbage and tomato, contains total energy of 340 kcal
with 61.8 g of carbohydrate, 7.7 g of fat, 4.8 g of protein,and 1.9 g of fiber. Subjects ate test meals consisting ofwhite rice and vegetable salad, eating either ‘vegetables
before carbohydrate’ or vice versa for 4 weeks. On eachtest day, patients came to the clinic at 8:45 in the morning
after a 12-hour overnight fast. After being weighed andhaving a fasting blood sample obtained, the patientsconsumed the test meals either eating rice first orvegetables first, chewing more than 20 times each bitewith a 10-min interval between rice and vegetables(Fig.1). Further blood samples were obtained at 30, 60,
and 120 minutes after the end of the meal. Plasma

Fig. 1glucose and insulin levels were evaluated at each test
meal. The subjects were instructed to maintain low
physical activity throughout the following 2 h of blood
sampling. The study protocol was approved by the Ethics
Committee of the School of Comprehensive
Rehabilitation at Osaka Prefecture University and allparticipants gave written informed consent prior toenrollment in the study. No changes were made to
antihypertensive and lipid-lowering therapies during thestudy in all groups.
No significant differences were found between mean
fasting blood glucose or insulin values in two of the test
days. Time course of plasma glucose and insulin levels
after consumption of the test meal in each test day wereshown in Fig.2. Postprandial plasma glucose levels of
eating vegetables before carbohydrates were reduced at
30 and 60 minutes compared to eating rice before
vegetables (Fig. 2A). Additionally, postprandial plasma
insulin levels of eating ‘vegetables before carbohydrate’
showed a significant decreased at 30 and 60 minutes
compared to eating rice before vegetables (Fig. 2B).
There was no significant difference in postprandial
plasma glucose levels at 120 minutes between each testday.
In this study, for the first time, we demonstrated thatthe effect of consuming vegetables before rice on
reducing the postprandial glucose and insulin levels insubjects with T2DM. These results suggest that eating
vegetables before carbohydrate may be beneficial for
subjects with postprandial hyperglycemia and T2DM.

Study protocol of crossover study of eating order diet.

Fig. 2Time course of (A) plasma glucose or (B) serum insulin at 0, 30, 60 and 120 minutes after eating rice before
vegetables (○) or the reverse regimen (●) (n = 15). Plasma glucose at 30 minutes after eating vegetables before rice
was significantly reduced compared to the reverse regimen ( p < 0.01). Serum insulin at 30 and 60 minutes after
following the same regimen ( p < 0.01) was also significantly reduced compared to the reverse regimen ( p < 0.05).
Data is expressed as mean ± SD. * p < 0.05, ** p < 0.01, rice first vs. vegetables first. Cited from Imai S et al.
(2010) J Japan Diab Soc, 53: 112-115

33 Retrospective study of the effect of eating‘vegetables before carbohydrate’ on long-term
glycemic control in Japanese patients with type 2
diabetes8
In addition to lowering acute postprandial glucose
and insulin responses, we evaluated the study todetermine whether educating diabetic patients to eat‘vegetables before carbohydrate’ was effective on longterm glycemic control. To test this hypothesis, we carriedout a retrospective study in patients with T2DM thatcompared changes in HbA1c as the primary outcome andchanges in weight, serum lipids, and blood pressure as thesecondary outcomes.
A total of 333 in 672 outpatients with T2DM in
Kajiyama Clinic were selected for possible participationin the study if they had no major complications or
medical illnesses. The protocol was approved by the
Ethics Committee of the School of Comprehensive
Rehabilitation at Osaka Prefecture University. Informed
consent was obtained from all the subjects. The patientswere divided into two groups to receive instructions on asimple meal plan of eating ‘vegetables before
carbohydrate’ (educational group, n = 196) without taking
into account of energy intake, or a control group (n =137) of taking medical examination by a doctor. All
patients were scheduled for return visits at every 4 weeks
with physical examination and patients in the educationalgroup were routinely scheduled to see dietitians at every
visit. Dietary practices and physical activity wereassessed in educational group.
The method of the education included nutritional
advice given in the form of a simple and easy meal planof eating ‘vegetables before carbohydrate’. In order toreduce postprandial hyperglycemia, patients in the
educational group were encouraged to consume every
meal eating vegetables prior to carbohydrate and chewing
each bite more than 20 times. Depending on the patient’s
current dietary intake, the intervention aimed toencourage increased consumption of vegetables,
mushrooms, and seaweeds using an original educational
brochure (Fig. 3). The intervention focused on setting
individual and realistic goals in order to achieve gradualdietary changes. Approximately 30 minutes were spent
on dietary counseling at the initial visit and 20 minutes at
each subsequent session. Dietary intake was assessed byfood records collected over three days at the initial visit(baseline) and over seven days after 2 months of theintervention. The dietitians were trained in all aspects of
instruction and coping skills, which include planningmenu and making appropriate food choices. Instructions
for the education regarding diet involved the same

Fig. 3 The educational brochure of eating vegetables before
carbohydrate for the patients with T2DM.

dietitian each time.
The dietary values were entered into a computer
database and analyzed by a dietitian, using a dietary
program (Eiyokun, Kenpakusha, Tokyo, Japan). Physicalactivity involving moderate exercise such as walking 30
to 40 minutes each day was recommended, and assessedin both groups using Kens Activity Monitor Life
Corders® (Suzuken, Aichi, Japan) for 7 days prior tointervention and 21 days after intervention. Dietary
restraint and overeating tendencies, such as emotional andexternal eating were measured using the Dutch Eating
Behavior Questionnaire (DEBQ).9 The patients wererequired to complete the DEBQ at the initial visit andafter 2 months of intervention. Emotional eating was
defined as eating in response to states of emotionalarousal such as fear, anger or anxiety, while external
eating was classified as eating in response to external
food cues such as the sight and the smell of food or eatingin response to food-related stimuli. Restrained eating was
defined as overeating after a period of slimming when the
cognitive resolve to diet was abandoned.
The control group involved the patients receiving
their usual outpatient management every 4 weeks. The
patients in the control group were given general
information about lifestyle and diabetes risk by either adoctor or nurse at every visit.
At baseline, the educational group and the control
group were comparable in sex, BMI and HbA1c, although
there were significant differences between the two groups
for mean age, duration of diabetes, systolic bloodpressure, and percentage of each therapy (Table 1). As
illustrated in Fig. 4, HbA1c levels decreased significantly
soon after intervention and over the 30-month follow-up
period in the educational group. Improvements in HbA1clevels over 30 months were observed from 8.3 to 7.1%

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Table 1

Fig. 4Characteristics of the patients in study groups

Changes in mean HbA1c levels in patients in the educational group (◆) and the control group (□)
over the 30-month follow-up period. Data is expressed as mean ± SE. Significant difference
from baseline, *** p < 0.001. Educational group vs. control group; # p < 0.05, ### p < 0.001.

with the educational group ( p < 0.001) while no change
was observed with the control group, from 7.8 to 7.7%,
and the values in the educational group were significantly
lower than the control group after 3 to 30 months of study
period. The improvements of glycemic control wereobserved in patients of the educational group whether
therapies or duration of DM after the intervention. The
levels of blood pressure, total cholesterol, and LDLcholesterol decreased significantly in both groups after 12

or 30 months (Table 2). Patients in the educational group
had a greater reduction in systolic blood pressure at both
12 and 30 months and showed higher HDL cholesterol
after 30 months compared to the control group. On theother hand, the diastolic blood pressure demonstrated aslight reduction in the control group after 30 months of
the intervention.
After the intervention, dietary energy intake, protein,
fat and carbohydrate were decreased in the educational

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Table 2

BMI, blood pressure , and serum lipids in study groups after the intervention

Table 3

Dietary intakes of before and after the intervention in the educational group

group (Table 3). These reductions of dietary nutrientswere the results of the decrease of the consumption ofgrain (rice), fruits, oil, sweets and beverages. On theother hand, consumption of vegetables increased after
intervention in the educational groups with a significant

increase in consumption of green vegetables. The energy
expenditure and eating behavior assessed by the DEBQ
demonstrated improved in the educational group after
intervention.

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4 Re-organize the nutritional strategies for helping
diabetic patients adhere to dietary regimensPatients with diabetes encounter several
psychological and lifestyle difficulties in modifying theirlives to achieve diabetic management.10 They exhibit
restrictive behaviors with regards to food intake and areconvinced that rigid dietary control is the only way toobtain good glycemic control. The approach of eating‘vegetables before carbohydrate’ was easier to understandand teach than other approaches. The most important
aspect was also easier to attain by making the appropriate
behavioral changes for participants. Our initial
hypothesis that the education of eating ‘vegetables before
carbohydrate’ would result in a more favorable dietary
regimen for participants. In this study, we demonstrated
that the effect of consuming vegetables before rice on the
reduction of the postprandial glucose and insulin levels insubjects with T2DM. In addition to lowering acutepostprandial glucose and insulin responses, our results
support the hypothesis that educating patients with T2DM
to eat ‘vegetables before carbohydrate’ was effective forachieving glycemic control for more than 2 years.
The reason for the reduction in postprandial glucose
levels in the ‘vegetables before carbohydrate’ can be
explained, partly, by the dietary fiber content in thevegetables taken before the carbohydrate.11,12 The diet ofthe educational group that was rich in dietary fiber
improved glucose tolerance by decreasing peak ofpostprandial glucose levels.13 These results indicated that
dietary carbohydrates consumed after vegetables weredigested slowly and required less insulin for subsequent
metabolic disposal. These changes would be expected tobenefit subjects with diabetes, as they often delay
secretion of insulin. 10 Numerous other factors may
influence the glycemic response and digestion ofcarbohydrates in the small intestine. These include therate of digestion,14 type of food,15 cooking method,16 typeof starch,17 presence of α-amylase inhibitors,17,18 transit
time, 19 amount of protein and fat, 20 rate of gastric
emptying, 21 rate of intestinal absorption, 22 hormonal
gastrointestinal response,23 hepatic glucose balance, andcellular metabolism of glucose. The patients in the
educational group showed increased post-meal satiety anddecreased subsequent hunger since they consumed acertain amounts of vegetables. This led them to decrease
the intake of carbohydrate at the end of each meal.
However, further studies are required to determine thedetails of the mechanisms responsible for these metabolicchanges.
The aim of the study was to re-organize nutritional
strategies for helping diabetic outpatients adhere todietary regimens. We observed a significant reduction in
HbA1c, blood pressure, body weight, and serum lipids
levels in the educational group. The patients in the
educational group had a significant increase in
consumption of green vegetables and other vegetables,
and a decreased consumption of grains and fruits
compared to before the intervention. These findings areimportant, as they suggest the strategy of eating‘vegetables before carbohydrate’ was successful inpromoting patient’s education, particularly regarding
consumption of food components. Although the strategyof education did not focus on restricting energy intake,the results showed patients reduced their intake of energy
intake after intervention.
In our previous study, we also demonstrated theeffect of this eating order method for the group educationon the reduction of glycated hemoglobin, body weight,
and serum lipids values in the participants with impaired
glucose tolerance.24 Additionally, participants showed
improvements in their 2-hour postprandial blood glucose
levels.
This approach of eating ‘vegetables before
carbohydrate’ supports the concept of emphasizing foodchoices, what to eat first, how to eat and not just toconcentrate on energy intake. With regard to nutritional
approaches, our research showed nutritional advice
should be given to patients with T2DM in the form of asimple and easy education, eating ‘vegetables before
carbohydrate’.
References
1 Nathan DM (1993) Long-term complications ofdiabetes mellitus. N Engl J Med, 328: 1676-1685.
2 UK Prospective Diabetes Study (UKPDS) Group(1998) Effect of intensive blood-glucose control
with metformin on complications in overweightpatients with type 2 diabetes (UKPDS 34). Lancet,
352: 854-865.
3 Bloomgarden ZT, Karmally W, Metzger MJ,
Brothers M, Nechemias C, Bookman J, Faierman D,
Ginsberg-Fellner F, Rayfield E, Brown WV (1987)
Randomised, controlled trial of diabetic patient
education: improved knowledge without improved
metabolic status. Diabetes Care, 10: 263-272.
4 Saaddine JB, Cadwell B, Gregg EW, Engelgau MM,
Vinicor F, Imperatore G, Narayan KM (2006)
Improvements in diabetes processes of care andintermediate outcomes: United States, 1988-2002.
Ann Intern Med, 144: 465-474.
5 Peyrot M, Rubin RR, Lauritzen T, Snoek FJ,
Matthews DR, Skovlund SE (2005) Psychosocial

7

6

7

8

9

10

11

12

13

14

problems and barriers to improved diabetes
management: results of the Cross-National Diabetes
Attitudes, Wishes and Needs (DAWN) Study. Diabet
Med, 22: 1379-1385.
Tominaga M, Eguchi H, Manaka H, Igarashi K, Kato
T, Sekikawa A (1999) Impaired glucose tolerance is
a risk factor for cardiovascular disease, but not
impaired fasting glucose: the Funagata diabetes
study. Diabetes Care, 22: 920-924.
Imai S, Matsuda M, Fujimoto S, Miyatani S,
Hasegawa G, Fukui M, Morigami M, Ozasa N,
Kajiyama S (2010) Crossover study of the effect of“vegetables before carbohydrates” on reducing
postprandial glucose and insulin in Japanese subjects
with type 2 diabetes mellitus. J Japan Diab Soc, 53:
112-115.
Imai S, Matsuda M, Togawa C, Oyabu K, Kajiyama
S (2010) Effect of eating ‘vegetables before
carbohydrates’ on glycemic control in Japanese
outpatients with type 2 diabetes. Journal of The
Japan Dietetic Association, in press
Van Strien T, Van de Laar FA (2008) Intake ofenergy is best predicted by overeating tendency andconsumption of fat is best predicted by dietary
restraint: A 4-year follow-up of patients with newly
diagnosed Type 2 diabetes. Appetite, 50: 544-547.
Snoek FJ (2000) Barriers to good glycaemic control:
the patient's perspective. Int J Obes Relat Metab
Disord, 24: S12-20.
Howarth NC, Saltzman E, Roberts SB (2001)
Dietary fiber and weight regulation. Nutr Rev, 59:
129-139.
Wong JM, Jenkins DJ (2007) Carbohydrate
digestibility and metabolic effects. J Nutr, 137:
S2539-2546.
McIntosh M, Miller C (2001) A diet containing foodrich in soluble and insoluble fiber improves
glycemic control and reduces hyperlipidemia among
patients with type 2 diabetes mellitus. Nutr Rev, 59:
52-55.
Anderson IH, Levine AS, Levitt MD (1981)
Incomplete absorption of the carbohydrate in allpurpose wheat flour. N Engl J Med, 304: 891-892.

15 Jenkins DJ, Wolever TM, Taylor RH, Barker H,
Fielden H, Baldwin JM, Bowling AC, Newman HC,
Jenkins AL, Goff DV (1981) Glycemic index offoods: a physiological basis for carbohydrateexchange. Am J Clin Nutr, 34: 362-366.
16 Sheard NF, Clark NG, Brand-Miller JC, Franz MJ,
Pi-Sunyer FX, Mayer-Davis E, Kulkarni K, Geil P(2004) Dietary carbohydrate (amount and type) in
the prevention and management of diabetes: astatement by the American Diabetes Association.
Diabetes Care, 27: 2266-2271.
17 O'Dea K, Nestel PJ, Antonoff L (1980) Physicalfactors influencing postprandial glucose and insulin
responses to starch. Am J Clin Nutr, 33: 760-765.
18 Yoon JH, Thompson LU, Jenkins DJ (1983) The
effect of phytic acid on in vitro rate of starchdigestibility and blood glucose response. Am J Clin
Nutr, 38: 835-842.
19 Englyst HN, Kingman SM, Cummings JH (1992)
Classification and measurement of nutritionally
important starch fractions. Eur J Clin Nutr, 46: S3350.
20 Thorne MJ, Thompson LU, Jenkins DJ (1983)
Factors affecting starch digestibility and theglycemic response with special reference to legumes.
Am J Clin Nutr, 38: 481-488.
21 Holt S, Heading RC, Carter DC, Prescott LF, TothillP (1979) Effect of gel fibre on gastric emptying andabsorption of glucose and paracetamol. Lancet, 313:
636-639.
22 Schwartz SE, Levine GD (1980) Effects of dietaryfiber on intestinal glucose absorption and glucose
tolerance in rats. Gastroenterology, 79: 833-836.
23 Amori RE, Lau J, Pittas AG (2007) Efficacy andsafety of incretin therapy in type 2 diabetes:
systematic review and meta-analysis. JAMA, 298:
194-206.
24 Imai S, Kozai H, Naruse Y, Watanabe K, Fukui M,
Hasegawa G, Obayashi H, Nakamura N, Naito Y,
Yoshikawa T, Kajiyama S (2008) Randomized
controlled trial of two forms of self-management
group education in Japanese people with impaired
glucose tolerance. J Clin Biochem Nutr, 43: 82-87.