My husband has the same problem but is adding weight slowly but surely now.
Try drinking protein shakes. A good brand is from Target - Whey Protein. You can mix it with water and add some berries.
Eating throughout the day, snacks like nuts and berries.
We also cook a lot of PALEO meals from http://paleomg.com/
The Paleo diet can be low carb and high protein and very healthy! No processed foods or chemicals.
Hope this help!
Yes. Eat more 'healthy' and naturally occuring fats.
For persons with diabetes, the optimal diet (for making blood sugar control easier) is one which is low in carbohydrates, moderate in protein (approx. 1g/kg body weight) and high in naturally occuring fats.
Your diet should also be high in vegetables (limit starchy veges such as potato, corn, etc, and also not too much fruit, particularly tropical fruits, which are very sweet), which are important for good nutrition.
Adding good fat (olive oil to name one) to your diet will raise your caloric intake.