Rhubarb

As William says, if you continue to loose at around 40 carb g, then don't worry.

To up your calories I suggest adding sugar free mayonnaise with your salad, add butter to your vegetables, perhaps have a high fat snack, such as nuts or low carb cheesecake, or add cream or cream cheese. With the latter items, keep a check on the carb content as well.

The idea of keeping the high calorie level is to make your body think there is plenty of food available and not to conserve what it has, as in a famine or restrictive diet. This will lower your metabolism and consequently slow your weight loss.

Having lots of fat and not much carbs means that much of the fat just goes straight through the gut and only what you need is used by the body for repairs and energy. It is highly unlikely to end up as fat on your body, unless you increase the carbs.