I Am 60 Yeras Old 67 Kg Wt, Am Hypertensive

I am 60 yeras old 67 kg wt, am hypertensive patient for past 7 years on Telma 40 BD , now under control. Diabetic past 3 years taking metoformin 500 BD under control. HbA1c =6%. My fasting sugar varies from 100-125 and pp after lunch 120-150. But pp after dinner is 160 mg/dl. why this variation in pp readings from lunch to dinner.