Have you eaten certain foods and after finishing your meal you can’t move? There may be something in that meal you are allergic to. The diet food your friend ate worked for them, but not for you. You made a list of food for the day, weighed yourself the next day and you have a weight increase of 2 to 4lbs. You may be allergic to some of the foods you eat. A bad reaction to certain foods for your body will cause weight gain. After your meal do you have feelings of fatigue, can’t think straight, you just want to fall asleep? Do you feel drunk after your meal? These all may be signs of food allergies.
You can correct food allergies by eliminating the foods you are allergic to. Try writing down what you eat and write how you feel after the meal. The purpose of food is to give the body energy.
Author Lyn-Genet Recitas stated “Constant exposure to a food can trigger an inflammatory response that packs on fat”. She stated the inflammation stops digestion and slows down your metabolism. This lowers the body’s ability to burn calories, causing the body to restore fluids and fat. A study performed at the Ranqueil Institute in France found that the more allergic your body is to a food item the greater weight gain a person had. They found in their studies the more sensitive you are to a food item, your body mass index (BMI) was more than six times higher than a person not as sensitive to same food item. Therefore are you gaining weight because you ate an item you thought was fattening or are you gaining weight because you are allergic to the food item that disagree with your body.
Beyond the Doctors Office: What's Next? 
That feeling lethargy after a meal can be food allergies, but it can also be insulin resistance. It’s advisable to have this checked by a health professional, especially one who practices “functional medicine.”
Thanks for sharing!