TWI849965B - System and method for detecting change in waist size - Google Patents

Abstract

A system for detecting change in waist size is provided, which includes a processing unit, a length measuring unit, a satiation degree and eating speed evaluation unit, and a warning unit. The processing unit calculates warning thresholds of satiation degree and eating speed according to the waist size of the user, and the length measurement unit is used for measuring a variation of the user's waist size. The satiation degree and eating speed evaluation unit determines whether the variation of the user's waist size and waist change speed exceed the warning thresholds of the satiation degree and eating speed. The warning unit sends out a warning signal when the variation of the user's waist size exceeds the warning threshold of the satiation degree and/or when the change speed of the user's waist size exceeds the warning threshold of the eating speed.

Description

System and method for detecting waist circumference changes

The present invention relates to a detection system and method thereof, and in particular to a system and method thereof for detecting waist circumference changes.

Modern people have irregular three meals a day, coupled with work pressure and the influence of the "all you can eat" culture, often overeating, eating two to three times the stomach capacity in one meal. Over time, in addition to causing indigestion, the stomach will also be enlarged and often feel hungry, which is also the main reason why many modern people are obese. After the stomach is enlarged, it will naturally squeeze other organs. At the same time, the blood supply in the stomach is limited. After the stomach becomes enlarged, it will also rob other organs of blood supply, thus causing diseases and affecting health.

The present invention relates to a system and method for detecting waist circumference changes, which can measure the waist circumference change of the user in real time and send out a warning signal when the waist circumference change of the user exceeds the warning threshold set by the system, so as to maintain the health of the user.

According to one aspect of the present invention, a system for detecting waist circumference changes is provided, comprising a processing unit, a length measurement unit, a satiety and eating speed evaluation unit, and a warning unit. The processing unit calculates the satiety and eating speed warning thresholds according to the user's waist circumference, and the length measurement unit is used to measure the waist circumference change of the user. The satiety and eating speed evaluation unit determines whether the waist circumference change and waist circumference change speed of the user exceed the satiety and eating speed warning thresholds. The warning unit sends a warning signal when the waist circumference change of the user exceeds the satiety warning threshold and/or when the waist circumference change speed of the user exceeds the eating speed warning threshold.

According to one aspect of the present invention, a method for detecting waist circumference changes is proposed, which is used in a system for detecting waist circumference changes. The warning thresholds of satiety and eating speed are calculated according to the waist circumference of the user. The waist circumference change of the user is measured. It is determined whether the waist circumference change of the user and the waist circumference change speed exceed the warning thresholds of satiety and eating speed. When the waist circumference change of the user exceeds the warning threshold of satiety and/or the waist circumference change speed of the user exceeds the warning threshold of eating speed, a warning signal is issued.

In order to better understand the above and other aspects of the present invention, the following is a specific example and a detailed description with the attached drawings as follows:

100: System for detecting waistline changes

101: System control terminal

102: Application Programming Interface

110: Processing unit

111: Length measurement unit

112: Satiety and eating speed assessment unit

113: Warning unit

114: Display unit

115: Storage unit

116: Motion sensing unit

117: Wireless communication module

θ: Tilt angle

S11~S15,S21~S25,S31~S35: Steps

S110~S120: Steps

Figure 1 is a schematic diagram of a system for detecting waist circumference changes in an embodiment of the present invention; Figures 2A to 2C are schematic diagrams of an application program interface in an embodiment of the present invention; Figures 3A to 3C are setting modes for satiety and eating speed reference values in an embodiment of the present invention; Figures 4A and 4B are measurement results of waist circumference changes before and after correction; Figures 5A to 5C are schematic diagrams showing how the user's sitting posture affects waist circumference measurement results; Figure 6 is a schematic diagram of a method for detecting waist circumference changes in an embodiment of the present invention.

Please refer to FIG. 1, which shows a schematic diagram of a system 100 for detecting waist circumference changes according to an embodiment of the present invention. The system 100 includes a processing unit 110, a length measuring unit 111, a satiety and eating speed evaluation unit 112, a warning unit 113, a display unit 114, a storage unit 115, a motion sensing unit 116, and a wireless communication module 117. The processing unit 110 can be an integrated circuit component such as a central processing unit, a chipset, etc. The length measuring unit 111 can be a potentiometer or a displacement sensor tied to the waist (referred to as an electronic belt for short), which can measure the waist circumference, and the accuracy of the waist circumference can reach about 1 mm. The displacement sensor can be mechanical or electronic, and can convert the measured physical quantity into electrical quantity (such as resistance). The displacement of the measured object (such as waist circumference) causes the resistance of the moving end of the potentiometer to change. The change in resistance reflects the value of the displacement, and whether the resistance increases or decreases indicates the direction of the displacement. The system control end 101 of the present system may include hardware and software. The satiety and eating speed evaluation unit 112 may be a software (application), and the warning thresholds of satiety and eating speed can be set according to the individual. The warning unit 113 may be an LED light, a vibrator, a buzzer, etc. The display module may be a liquid crystal display. The storage unit 115 may be a flash memory or a memory card. The motion sensing unit 116 may be a three-axis gravity acceleration sensor or an angle sensor. The wireless communication module 117 can be a wireless transceiver module such as WiFi, Bluetooth or radio frequency signal.

In one embodiment, the processing unit 110 calculates the warning thresholds of satiety and eating speed according to the waist circumference of the user, and the length measuring unit 111 is used to measure the waist circumference change of the user. The satiety and eating speed evaluation unit 112 determines whether the waist circumference change and waist circumference change speed of the user exceed the warning thresholds of satiety and eating speed. The warning unit 113 sends a warning signal when the waist circumference change of the user exceeds the warning threshold of satiety and/or when the waist circumference change speed of the user exceeds the warning threshold of eating speed.

In addition to the system control terminal 101 described above, the system may also include a user interface for the user application terminal, such as a mobile phone application interface 102. Through the mobile phone application interface 102, the user can view the measurement data of the system control terminal 101, such as measurement time, measurement situation, waist circumference before meal, waist circumference after meal, satiety percentage, eating speed and other data. In addition, through the mobile phone application interface 102, the user can record his or her own health diary or upload his or her own health diary to the cloud server, so that professional doctors or medical staff can judge the personal health status.

Please refer to Figures 2A to 2C, which illustrate schematic diagrams of an application program interface 102 according to an embodiment of the present invention. In Figure 2A, through the mobile phone application program interface 102, the user can set the default length of the belt (e.g., 80 cm, 100 cm, 120 cm, and 140 cm), the hole position for the belt to be buckled (e.g., the 1st hole to the 5th hole), and input the cut-off length of the belt tail end for the system control terminal 101 to set the belt length. In addition, in Figure 2B, through the mobile phone application program interface 102, the user can set a personalized satiety standard, such as 0~50% (less than 50%) satiety range corresponding to green, 50~70% satiety range corresponding to orange, and 70% or more satiety range corresponding to red. In addition, in FIG. 2C, through the mobile phone application program interface 102, the user can obtain waist measurement data, such as waist length, satiety, waist length change chart, calculate the remaining measurement time, and record it in his or her health diary.

In addition, the satiety and eating speed assessment unit 112 uses the time point of "starting measurement" as the reference point for judging satiety to avoid the fluctuation of satiety over time and affect the accuracy of the measurement results. In addition, the system can calculate satiety and eating speed reference values for different users. The satiety and eating speed reference values include three modes: precise mode (Figure 3A), general mode (Figure 3B), and customized mode (Figure 3C). In the precise mode, each user first ties the length measurement unit 111 (electronic belt) around his or her waist and presses the start measurement. The user drinks 800cc of water and two slices of toast within 5 minutes. After completing the above-mentioned eating, wait for 10 minutes and end the measurement. The waist circumference change in these 15 minutes is set as the reference value of 100% satiety. The display unit 114 and the application program interface 102 can display different colors for different satiety intervals, for example, less than 50% satiety interval corresponds to green, 50-70% satiety interval corresponds to orange, and more than 70% satiety interval corresponds to red.

In addition, when measuring the eating speed, each user first tied the length measuring unit 111 (electronic belt) around his waist and drank 300cc, 600cc, or 900cc of water within 15 minutes. Drinking 300cc of water within 15 minutes, the waist circumference change is L300, and the waist circumference change speed (i.e. slope) is m300=L300/15, which is a reference value for normal eating speed. When the waist circumference change speed is less than m300, it means the eating speed is normal; drinking 600cc of water within 15 minutes, the waist circumference change is L600, and the waist circumference change speed (i.e. slope) is m600=L600/15, which is a reference value for eating too fast. When the waist circumference change speed is less than m600, it means eating too fast; drinking 900cc of water within 15 minutes, the waist circumference change is L900, and the waist circumference change speed (i.e. slope) is m900=L900/15, which is a reference value for eating too fast. When the waist circumference change speed is less than m900, it means eating too fast. These eating speed reference values m300, m600, and m900 can be recorded in the storage unit 115 of the system. When the user's eating speed exceeds one of the above eating speed reference values m300, m600, and m900, the system will issue a warning to notify the user.

As shown in Figure 3A, the waist circumference measured before eating (hereinafter referred to as the first waist circumference) is used as the starting value (step S11), then the eating time is calculated (step S12), and the waist circumference measured after eating (hereinafter referred to as the second waist circumference) is used as the measurement value (step S13), and the waist circumference change is calculated using the first waist circumference and the second waist circumference (step S14). Then, according to the waist circumference change, the satiety reference value and the eating speed reference value are calculated (step S15).

On the other hand, the personalized satiety reference value is positively correlated with waist circumference. The following experimental measurements show that even for subjects with the same BMI, the measured 100% satiety reference value is still different. Therefore, it is necessary to measure and set the satiety reference value according to different users. Taking subject A as an example, with a waist circumference of 97 cm, the 100% satiety reference value can be set to 14mm. The waist circumference change corresponding to the 0~49% satiety interval is less than 7mm, the waist circumference change corresponding to the 50~70% satiety interval is greater than or equal to 7mm and less than or equal to 9.8mm, and the waist circumference change corresponding to the 70% or more satiety interval is greater than 9.8mm. These satiety reference values of 7mm, 9.8mm, and 14mm can be recorded in the storage unit 115 of this system. When the user's waist circumference changes to the above satiety reference values, the system will notify the user of the current satiety status.

On the other hand, the eating speed and waist circumference change of different users are different. The following experimental measurements show that even for subjects with the same BMI, the measured eating speed reference values are still different. Therefore, it is necessary to customize the eating speed reference value according to different users. Take subject A as an example, with a waist circumference of 97 cm, drinking 900cc, 600cc, and 300cc of water in 15 minutes, the waist circumference changes are 7mm, 5mm, and 3mm respectively, and the waist circumference change speed is 7mm/15min, 5mm/15min, and 3mm/15min respectively, as the eating speed reference value. When the user's eating speed exceeds one of the above eating speed reference values, the system will issue a warning to notify the user. In addition, since the change in waist circumference is positively correlated with the amount of food eaten, the following experimental data shows that the ratio of the waist circumference changes of the three subjects is approximately 3:2:1. Therefore, the eating speed measurement can be changed to only measure the waist circumference change after drinking 900cc of water to reduce the measurement time.

2，其中x表示腰圍長度，y表示100%飽食度的腰圍變化量，n為大於等於2的自然數。在本案揭露的實施例中，根據訓練資料集，建立五個多項式回歸方程式，從n=2至n=6，並依據資料與回歸線的差值平方來挑選最合適的飽食度評估模型。 In a general mode, the satiety and eating speed evaluation unit 112 may include a satiety evaluation model. As shown in FIG. 3B , waist circumference (and variation) in big data is first obtained and divided into a training data set and a test data set (step S21). The satiety evaluation model can be modeled by establishing a polynomial regression equation through the training data set (step S22). The training data sets of multiple users are analyzed through polynomial regression to summarize the correlation between the initial waist circumference length of the user and the waist circumference variation at 100% satiety, so as to obtain an ideal regression curve. The training data set includes the user's initial waist length and the waist change at 100% satiety measured by the length measurement unit 111 (electronic belt), and may also include test data simulating actual measurement data to increase the amount of training data. In one embodiment, the polynomial regression equation is, for example: y = w ₀ + w ₁ x ¹ +…+ w _n x ⁿ , n

2, where x represents waist circumference length, y represents waist circumference change at 100% satiety, and n is a natural number greater than or equal to 2. In the embodiment disclosed in this case, five polynomial regression equations are established based on the training data set, from n=2 to n=6, and the most suitable satiety assessment model is selected based on the square of the difference between the data and the regression line.

For example, when n=3, the result obtained by the least square method of the data and the regression line is used as the test error, and a model with the minimum test error can be obtained (step S23). Therefore, in this embodiment, the polynomial regression equation with n=3 is used as the most suitable satiety assessment model, but the present invention is not limited to this. When the user selects the general mode, the waist circumference change can be evaluated in real time through the satiety assessment model, and then the satiety reference value can be obtained, without the need to set the satiety reference value and eating speed reference value in advance through actual eating/drinking.

As shown in Figure 3B, when the model with the minimum prediction error is established, the first waist circumference is measured (step S24), and the first waist circumference is input into the model to output the corresponding satiety reference value and eating speed reference value (step S25). When the user's waist circumference change amount and change speed meet the above-mentioned satiety reference value and eating speed reference value, the system will notify the user of the current satiety status.

In the customized mode, users can learn from their own satiety feedback system by collecting a large amount of feedback data to generate a satiety reference value. Generally speaking, depending on the physical condition of each person, the brain will remind people that they have eaten too much about 15 to 30 minutes after eating. Therefore, the test time of the customized mode is set to 30 minutes. After eating for 30 minutes, the user enters how full they are based on the change in waist circumference. The system calibrates based on the data entered by the user, such as (waist circumference change Xmm, Y points of fullness). After complete and comprehensive data collection and data analysis, the system can obtain a more accurate satiety reference value.

As shown in FIG. 3C , the first waist circumference measured before eating is taken as the starting value (step S31), and then the eating time is calculated (step S32). If the eating time is, for example, more than 30 minutes, the second waist circumference measured after eating is taken as the measured value (step S33), and the waist circumference change is calculated with the first waist circumference and the second waist circumference (step S34). The waist circumference change is matched with the input satiety/eating speed and recorded (step S35). For example, subject A has a waist circumference of 97 cm, and the waist circumference change after eating for 30 minutes is 11 mm. The user's satiety after eating is 8 points full and is input into the system. Based on this reported data, the system can calculate the waist circumference change corresponding to the 100% satiety reference value as 14mm, and set the waist circumference change corresponding to the 0~49% satiety interval to be less than 7mm, the waist circumference change corresponding to the 50~70% satiety interval to be greater than or equal to 7mm and less than or equal to 9.8mm, and the waist circumference change corresponding to the 70% satiety interval to be greater than 9.8mm. When the user's waist circumference change and change speed meet the above-mentioned satiety reference value and eating speed reference value, the system will notify the user of the current satiety status.

During the actual measurement process, changes in the user's posture will affect the results of waist circumference measurement. For example, when the user's body leans forward or leans back, the measured waist circumference change will be abnormal. These abnormal data will affect the accuracy of satiety and eating speed, so the measurement data must be corrected to avoid excessive fluctuations in waist circumference changes. In one embodiment, a three-axis gravity acceleration sensor or an angle sensor is used to measure whether the user's posture has changed (for example, detecting the user's tilt angle). If the user's tilt angle is too large (exceeding a predetermined threshold), it will affect the waist circumference measurement results, and the waist circumference change will be corrected according to the tilt angle. If the user's tilt angle is less than the predetermined threshold and does not affect the waist measurement result, the measurement data will not be corrected.

Please refer to Figures 4A and 4B, which show the measurement results of waist circumference changes before and after calibration. The waist circumference change measured at each minute is based on the waist circumference at the beginning of measurement (0th minute), and the user's tilt angle is based on the angle at 0th minute. In one embodiment, the formula for calculating the tilt angle is as follows: △angle(n)=angle(n)-angle(0), n is a positive number, in this embodiment n is a positive integer, abs(△angle(n))≦preset angle, no correction is performed; abs(△angle(n))>preset angle, correction is performed according to the following algorithm, in this embodiment, the default angle is 20 degrees (but not limited to this), that is, the waist circumference change at the nth minute is corrected to the waist circumference change at the mth minute, m is a positive number less than n, and the abs(△angle(m)) at the mth minute is ≦20 degrees.

In Figure 4A, the waist circumference change value between the 5th minute and the 8th minute fluctuates rapidly, which may be caused by the user's body leaning forward or backward. For example, the user's posture at the beginning of the measurement (0th minute) is as shown in Figure 5A, and between the 5th minute and the 8th minute, the user's body first leans forward (as shown in Figure 5B) and then leans backward (as shown in Figure 5C). In this embodiment, since the tilt angle change measured at the 6th minute is greater than 20 degrees, the algorithm is activated to perform waist circumference correction, and the waist circumference change (e.g., 10 mm) at the 6th minute (n=6) is corrected to the waist circumference change (e.g., 7 mm) at the 5th minute (mth minute) as a reference point; similarly, since the tilt angle change measured at the 7th minute is still greater than 20 degrees, the waist circumference change (e.g., 5 mm) at the 7th minute is corrected to the waist circumference change at the 5th minute as a reference point. Until the tilt angle at the 8th minute is less than or equal to 20 degrees, the waist circumference change (e.g., 9 mm) at the 8th minute does not need to be corrected, and the algorithm processing is no longer performed after the 8th minute. Until the absolute difference abs(△angle(n)) is greater than 20 degrees again at the 22nd minute, the algorithm is activated again, and the 21st minute (the mth minute) is used as the reference point for the waist circumference change after the algorithm is activated. The waist circumference changes at the 22nd and 23rd minutes (for example, 9mm) are corrected to the waist circumference changes at the 21st minute (for example, 13mm) as the reference point. The processing method is roughly the same as the above content, and will not be repeated here. Figure 4B shows the corrected waist circumference change. After removing the user's posture change factor, it can more reasonably reflect the actual waist circumference change and reduce the measurement error.

Refer to Figures 5A to 5C, which show the effect of the user's sitting posture on the waist measurement results. In Figure 5A, when the user's sitting posture is correct and the user's tilt angle is less than 20 degrees, it will not affect the waist measurement results. In Figures 5B and 5C, when the user's body leans forward or backward, when the user's tilt angle θ is greater than or equal to 20 degrees, the waist circumference increases due to the body's pressure on the abdomen or decreases due to the body's stretching. Therefore, the actual waist circumference change can only be obtained after removing the user's posture change factor.

Please refer to Figure 6, which shows a schematic diagram of a method for detecting waist circumference changes according to an embodiment of the present invention. This method uses the time point of "starting measurement" as the reference point for determining satiety to avoid the satiety fluctuating over time and affecting the accuracy of the measurement results. In addition, this method can calculate satiety and eating speed reference values for different users. The satiety and eating speed reference values include three modes: precise mode, general mode, and customized mode. The system can calculate the satiety reference value, satiety and eating speed warning thresholds according to the selected mode.

The method for detecting waist circumference changes includes the following steps. In step S110, the warning thresholds of satiety and eating speed are calculated according to the selected mode. In step S111, the user ties the length measurement unit 111 (electronic belt) around his waist to obtain the initial value of the waist circumference. In step S112, the length measurement unit measures the user's waist circumference change. In step S113, the motion sensing unit (such as G sensor) detects the user's tilt angle. In step S114, when it is determined that the user's tilt angle is greater than the threshold, step S115 is entered to correct the waist circumference change according to the tilt angle. If the user's tilt angle is less than the threshold, no correction processing is performed. Next, in step S116, the satiety and eating speed evaluation unit 112 determines whether the waist circumference change of the user exceeds the satiety warning threshold. If the waist circumference change of the user exceeds the satiety warning threshold, the system proceeds to step S117, and the warning unit 113 sends a satiety signal, such as a light warning, a vibration warning, or a buzzer warning. Then, the system proceeds to step S118. In step S118, the system can calculate the eating speed according to the waist circumference change speed. In step S119, the satiety and eating speed evaluation unit 112 determines whether the user's waist circumference change speed exceeds the eating speed warning threshold. If so, the process proceeds to step S120, and the warning unit 113 issues an eating too fast warning to remind the user that he is eating too fast. For example, when the user's eating speed exceeds one of the above-mentioned eating speed reference values m300, m600, and m900, the system will issue a warning to notify the user.

In addition, in step S114, the threshold of the tilt angle is, for example, 20 degrees ± 5 degrees, which can be set according to the allowable sitting posture. In one embodiment, the formula for calculating the tilt angle is as follows: △angle(n)=angle(n)-angle(0), n is a positive integer, when abs(△angle(n))≦20 degrees, no correction processing is performed; when abs(△angle(n))>20 degrees, correction can be performed according to the algorithm.

In addition to the steps described above, the method for detecting waist circumference changes may also include transmitting data to the mobile phone's application program interface 102 through the wireless communication module 117, so that the user can view the measurement data of the system control terminal 101, such as measurement time, measurement situation, waist circumference before meal, waist circumference after meal, satiety percentage, eating speed, etc. In addition, through the mobile phone's application program interface 102, the method may also allow the user to record his or her own health diary or upload his or her own health diary to the cloud server, so that a professional doctor or medical staff can judge the personal health status.

The present invention discloses a system and method for detecting waist circumference changes in the above-mentioned embodiment, wherein the detection system includes a processing unit, a length measurement unit, a satiety and eating speed evaluation unit, and an alarm unit. The processing unit calculates the satiety and eating speed alarm thresholds according to the user's waist circumference, and the length measurement unit is used to measure the user's waist circumference change. The satiety and eating speed evaluation unit determines whether the user's waist circumference change and waist circumference change speed exceed the satiety and eating speed alarm thresholds. The alarm unit sends a warning signal when the user's waist circumference change exceeds the satiety alarm threshold and/or when the user's waist circumference change speed exceeds the eating speed alarm threshold. In this way, the system can measure the user's waist circumference change in real time and send out a warning signal when the user's waist circumference change exceeds the warning threshold set by the system to maintain the user's health.

100: System for detecting waistline changes

101: System control terminal

102: Application Programming Interface

110: Processing unit

111: Length measurement unit

112: Satiety and eating speed assessment unit

113: Warning unit

114: Display unit

115: Storage unit

116: Motion sensing unit

117: Wireless communication module

Claims (10)

A system for detecting waist circumference changes includes: a processing unit for calculating the warning thresholds of satiety and eating speed according to the waist circumference of the user; a length measuring unit for measuring the waist circumference change of the user; a satiety and eating speed evaluation unit for determining whether the waist circumference change and waist circumference change speed of the user exceed the warning thresholds of satiety and eating speed; a warning unit for sending a warning signal when the waist circumference change of the user exceeds the warning threshold of satiety and/or when the waist circumference change speed of the user exceeds the warning threshold of eating speed; and a motion sensing unit for detecting the tilt angle of the user, wherein the satiety and eating speed evaluation unit corrects the waist circumference change according to the tilt angle of the user. The system as described in claim 1, wherein the formula for calculating the tilt angle is as follows: △angle(n)=angle(n)-angle(0), when the absolute difference between the tilt angles at the nth minute and the 0th minute abs(△angle(n))≦the preset angle, the waist circumference change is not corrected; when the absolute difference between the tilt angles at the nth minute and the 0th minute abs(△angle(n))>the preset angle, the waist circumference change at the nth minute is corrected to the waist circumference change at the mth minute, m is less than n, and abs(△angle(m))≦the preset angle. The system as described in claim 1, wherein the satiety and eating speed evaluation unit uses the time point of "starting measurement" as the criterion point for judging satiety, wherein the satiety and eating speed evaluation unit sets satiety and eating speed reference values according to the waist circumference change amount and waist circumference change speed of the user, and when the waist circumference change amount of the user meets the satiety reference value, the warning signal is a satiety warning; when the waist circumference change speed of the user meets the eating speed reference value, the warning signal is an eating too fast warning. The system as described in claim 1, wherein the satiety and eating speed assessment unit includes a satiety assessment model, the satiety assessment model is modeled by a polynomial regression equation, and a polynomial regression equation with minimum test error is obtained by polynomial regression analysis to calculate the user's satiety. The system as described in claim 1, wherein the satiety and eating speed assessment unit sets a satiety reference value according to the waist circumference change and satiety input by the user, and when the waist circumference change of the user meets the satiety reference value, the warning signal is a satiety warning. A method for detecting waist circumference changes, used in a system for detecting waist circumference changes as described in claim 1, the method comprising: calculating the warning thresholds of satiety and eating speed according to the waist circumference of the user; measuring the waist circumference change of the user; detecting the tilt angle of the user, and correcting the waist circumference change according to the tilt angle of the user; determining whether the waist circumference change and waist circumference change speed of the user exceed the warning thresholds of satiety and eating speed; When the waist circumference change of the user exceeds the warning threshold of satiety and/or the waist circumference change speed of the user exceeds the warning threshold of eating speed, a warning signal is issued. The method as described in claim 6, wherein the formula for calculating the tilt angle is as follows: △angle(n)=angle(n)-angle(0), n is a positive integer, when the absolute difference between the tilt angles at the nth minute and the 0th minute abs(△angle(n))≦the preset angle, the waist circumference change is not corrected; when the absolute difference between the tilt angles at the nth minute and the 0th minute abs(△angle(n))>the preset angle, the waist circumference change at the nth minute is corrected to the waist circumference change at the mth minute, m is less than n, and abs(△angle(m))≦the preset angle. As described in claim 6, the satiety and eating speed evaluation unit uses the time point of "starting measurement" as the criterion point for judging satiety, wherein the satiety and eating speed evaluation unit sets satiety and eating speed reference values according to the waist circumference change amount and waist circumference change speed of the user, and when the waist circumference change amount of the user meets the satiety reference value, the warning signal is a satiety warning; when the waist circumference change speed of the user meets the eating speed reference value, the warning signal is an eating too fast warning. The method as described in claim 6, wherein the satiety and eating speed assessment unit includes a satiety assessment model, the satiety assessment model is modeled by a polynomial regression equation, and a polynomial regression equation with a minimum test error is obtained by polynomial regression analysis to calculate the user's satiety. The method as described in claim 6, wherein the satiety and eating speed assessment unit sets a satiety reference value according to the waist circumference change and satiety input by the user, and when the waist circumference change of the user meets the satiety reference value, the warning signal is a satiety warning.

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