Your puppy likely is starving. As Holly said, but it bears repeating - it is important to meet the needs of your dog based on her weight, energy requirements, and activity level.
In the raw world, it has become the norm to say feed x% - but this is very erroneous and most dogs don't necessarily do well or fit with a norm %. It is no more valid for me to say I eat x Lbs. of food a day so you should too
Nonetheless, commercial raw food providers tell you to feed 5-6% of body weight per day for growing puppies - usually amounting to about 3 lbs. of food a day based on meat, bone, and produce. I can tell you that I have never fed a puppy this age LESS than 3 lbs a day - based on activity level and energy requirements.
So since you didn't say WHAT you are feeding - it is hard to assess. 1 lb. of beef is very different in calories, fat and protein than 1 lb. of green beans so WHAT you are feeding and the quantity of those ingredients is what matters here. Many raw feeders, especially prey model, feed very high fat diets - so this will dictate less food (to meet the same amount of calories). The more produce, and non fat items comprise the diet, the more food needed (to meet required calories).
To help, I am guessing your pup is about 45 lbs. give or take? Let us know. If so, a 5 month old, 45 lb Berner requires approximately 2,800 calories per day and you couldn't be any where close to that in the quantity of food you're feeding. It is critical not to grow these dogs too fast (provide too many calories) so you want to strive for 2 lbs. per week - they will hit two big growth spurts at about 4 month and again between 8-9 and may grow a little more but if you are hitting more than 3 lbs. per week, slow down as you are growing her too fast.
If your pup is gaining 2 lbs. per week, you can feel her ribs, but not the sides of her spine on her back - she is good. If you can feel her spine and hip bones too prominately, she is underfed.
The NRC sets the recommended allowances for dogs and cats and states that a growing puppy after 14 weeks of age has the following RAs based on kg weight (rather than lbs.):
Calcium (mg) 680
Phosphorus (mg) 680
Magnesium (mg) 27.4
Sodium (mg) 100
Potassium (mg) 300
Chloride (mg) 200
Iron (mg) 6.1
Copper (mg) 0.76
Zinc (mg) 6.84
Manganese (mg) 0.38
Selenium (ug) to (mcg) 25.1
Iodine (ug) to (mcg) 61
A (RE) 105
E (mg) 2.1
K (mg) 0.11
Thiamin (mg) 0.096
Riboflavin (mg) 0.37
Pyridoxine (mg) B6 0.1
Niacin (mg) 1.18
Pantothenic Acid (mg) 1.04
Folic Acid (ug) 18.8
Choline (mg) 118
Cholecalcifero
l (ug) D 0.96
Cobalimin (ug) B12 2.4
Arginine (mg) 460
Histidine (mg) 170
Isoleucine (mg) 350
Methionine (mg) 180
Cystine (mg) 370
Leucine (mg) 570
Lysine (mg) 490
Phenylalanine (mg) 350
Phenylalanine & Tyrosine (mg) 700
Threonine (mg) 440
Tryptophan (mg) 130
Valine (mg) 390
This means that a 5 month old, 45 lb. puppy requires more than 6,500 mg of calcium and phosphorus and almost 2,900 mg of potassium for example. This is significantly more than she will require as an adult and is at its peak about now - so it is critical to ensure you are meeting her needs for proper development.