Gaining

Have the heavy cream with dinner or for dessert. Do not drink it after 7 PM. You have acid reflux from it, which is caused by increased acid production in response to the fat in the cream. Pepsid and other similar acid inhibitors may help.

What Fatowl is saying is to have the cream after you have finished eating for the day but several hours before going to bed if possible. This will get a lot of the digestive process done before you lie down, which often puts pressure on the stomach. I speak from experience here. Having said that, it does depend on the amount of cream. I find I can take 300ml just before bed and be OK. Any more and I have the problems you describe. YMMV - The trick is finding out what you can get away with.

It takes about 2 hours to digest fats. If you drink your heavy whipping cream at least two hours before going to sleep, you should be okay.

last month i did 600ml of double cream everyday, with 1 day as a break on top of overeating. i gave up after 2 weeks because i didnt gain anything. been averaging 5000 a day this month on normal food and still havent gained anything. am i defying the laws of nutrition or something? its really depressing and frustrating

How are you drinking it? Are you drinking it all at once, or spreading it out throughout the day?

The body can only absorb about 1,000 calories of fat at one sitting, and it takes at least 2 hours to digest the fat. If you drink more fat than this in one sitting, you're probably wasting the excess calories.

i think it might have, i still weighed the same last night, i got upset and depressed

That’s rough. My experience is similar to others here: The most effective way to consume double cream is to spread it out over hours. When I use it, I tend to drink 600ml over about 4 hours, in the morning/early afternoon. This way, I don’t experience the internal “heaviness” and I avoid it crushing my appetite.

If you’re over-consuming calories but not gaining fat, then you’re not absorbing those calories. This is normal, as we don’t absorb every nutrient that we consume, however it might be worth spending some time considering your digestive health and eating habits to see if you might find ways to optimise your calorie absorption.