diff --git a/app/models/food.rb b/app/models/food.rb
index a8f19bd..696857e 100644
--- a/app/models/food.rb
+++ b/app/models/food.rb
@@ -16,12 +16,16 @@ class Food < ActiveRecord::Base
   belongs_to :ref_unit, class_name: 'Unit', required: true
   belongs_to :source, required: false
   has_many :ingredients, dependent: :restrict_with_error
+  has_many :nutrients, foreign_key: 'registry_id', inverse_of: :food, dependent: :destroy,
+    validate: true
+
+  DOMAIN = :diet
+  alias_attribute :subitems, :nutrients
+  scope :subitems, -> { includes(nutrients: [:quantity, :unit]) }
 
-  has_many :nutrients, inverse_of: :food, dependent: :destroy, validate: true
   validates :nutrients, presence: true
-  accepts_nested_attributes_for :nutrients, allow_destroy: true, reject_if: proc { |attrs|
-    attrs['quantity_id'].blank? && attrs['amount'].blank?
-  }
+  accepts_nested_attributes_for :nutrients, allow_destroy: true,
+    reject_if: proc { |attrs| attrs['quantity_id'].blank? && attrs['amount'].blank? }
   # Nutrient quantity_id uniqueness check for nested attributes
   validate do
     quantities = self.nutrients.reject { |n| n.marked_for_destruction? }
diff --git a/app/models/ingredient.rb b/app/models/ingredient.rb
index e7e47cf..d2c5215 100644
--- a/app/models/ingredient.rb
+++ b/app/models/ingredient.rb
@@ -2,6 +2,11 @@ class Ingredient < ActiveRecord::Base
   belongs_to :composition, inverse_of: :ingredients, polymorphic: true, required: true
   belongs_to :food, required: true
   belongs_to :part_of, required: false
+  has_many :nutrients, through: :food, source: :nutrients
+
+  DOMAIN = :diet
+  alias_attribute :subitems, :nutrients
+  scope :subitems, -> { includes(nutrients: [:quantity, :unit]) }
 
   validates :ready_ratio, numericality: {greater_than_or_equal_to: 0.0}
   validates :amount, numericality: {greater_than_or_equal_to: 0.0}
diff --git a/app/models/measurement.rb b/app/models/measurement.rb
index 87685fa..48e87d9 100644
--- a/app/models/measurement.rb
+++ b/app/models/measurement.rb
@@ -1,19 +1,22 @@
 class Measurement < ActiveRecord::Base
   belongs_to :routine, required: true, inverse_of: :measurements,
     class_name: 'MeasurementRoutine'
-  accepts_nested_attributes_for :routine, allow_destroy: true, reject_if: proc { |attrs|
-    attrs['name'].blank?
-  }
-  after_destroy { self.routine.destroy if self.routine.measurements.empty? }
-  has_one :project, through: :routine
-
   belongs_to :source, required: false
+  has_one :project, through: :routine
+  has_many :readouts, foreign_key: 'registry_id', inverse_of: :measurement,
+    dependent: :destroy, validate: true
+
+  DOMAIN = :measurement
+  alias_attribute :subitems, :readouts
+  scope :subitems, -> { includes(readouts: [:quantity, :unit]) }
+
+  accepts_nested_attributes_for :routine, allow_destroy: true,
+    reject_if: proc { |attrs| attrs['name'].blank? }
+  after_destroy { self.routine.destroy if self.routine.measurements.empty? }
 
-  has_many :readouts, inverse_of: :measurement, dependent: :destroy, validate: true
   validates :readouts, presence: true
-  accepts_nested_attributes_for :readouts, allow_destroy: true, reject_if: proc { |attrs|
-    attrs['quantity_id'].blank? && attrs['value'].blank?
-  }
+  accepts_nested_attributes_for :readouts, allow_destroy: true,
+    reject_if: proc { |attrs| attrs['quantity_id'].blank? && attrs['value'].blank? }
   # Readout quantity_id + unit_id uniqueness validation. Cannot be effectively
   # checked on Readout model level.
   validate do
diff --git a/app/models/nutrient.rb b/app/models/nutrient.rb
index f896bd4..c7f6e46 100644
--- a/app/models/nutrient.rb
+++ b/app/models/nutrient.rb
@@ -1,9 +1,10 @@
 class Nutrient < QuantityValue
-  belongs_to :food, inverse_of: :nutrients, required: true
+  belongs_to :food, foreign_key: 'registry_id', inverse_of: :nutrients, required: true
 
-  validates :value, numericality: {greater_than_or_equal_to: 0.0}
   # Uniqueness NOT validated here, see Value for explanation
   #validates :quantity, uniqueness: {scope: :food_id}
+  validates :value, numericality: {greater_than_or_equal_to: 0.0}
 
   alias_attribute :amount, :value
+  delegate :ref_amount, to: :food
 end
diff --git a/app/models/readout.rb b/app/models/readout.rb
index ca72b6d..52de298 100644
--- a/app/models/readout.rb
+++ b/app/models/readout.rb
@@ -1,7 +1,7 @@
 class Readout < QuantityValue
-  belongs_to :measurement, inverse_of: :readouts, required: true
+  belongs_to :measurement, foreign_key: 'registry_id', inverse_of: :readouts, required: true
 
-  validates :value, numericality: true
   # Uniqueness NOT validated here, see Value for explanation
   #validates :quantity, uniqueness: {scope: [:measurement_id, :unit_id]}
+  validates :value, numericality: true
 end
diff --git a/lib/body_tracking/items_with_quantities.rb b/lib/body_tracking/items_with_quantities.rb
index 69946c5..8d52dad 100644
--- a/lib/body_tracking/items_with_quantities.rb
+++ b/lib/body_tracking/items_with_quantities.rb
@@ -1,23 +1,5 @@
 module BodyTracking
   module ItemsWithQuantities
-    ITEM_TYPES = {
-      'Ingredient' => {
-        domain: :diet,
-        associations: [:food, :nutrients],
-        value_field: :amount
-      },
-      'Food' => {
-        domain: :diet,
-        associations: [:nutrients],
-        value_field: :amount
-      },
-      'Measurement' => {
-        domain: :measurement,
-        associations: [:readouts],
-        value_field: :value
-      }
-    }
-
     def filter(filters, requested_q = nil)
       items = all
 
@@ -33,11 +15,10 @@ module BodyTracking
         if filters[:formula][:code].present?
           owner = proxy_association.owner
           project = owner.is_a?(Project) ? owner : owner.project
-          domain = ITEM_TYPES[proxy_association.klass.name][:domain]
           filter_q_attrs = {
             name: 'Filter formula',
             formula_attributes: filters[:formula],
-            domain: domain
+            domain: proxy_association.klass::DOMAIN
           }
           project.quantities.new(filter_q_attrs)
         end
@@ -56,23 +37,10 @@ module BodyTracking
     def compute_quantities(requested_q, filter_q = nil)
       items = all
 
-      item_type = ITEM_TYPES[proxy_association.klass.name]
       subitems = Hash.new { |h,k| h[k] = {} }
-      # Ingredient.includes(food: {nutrients: [:quantity, :unit]}).order('quantities.lft')
-      # Food.includes(nutrients: [:quantity, :unit]).order('quantities.lft')
-      includes = item_type[:associations].reverse
-        .inject([:quantity, :unit]) { |relation, assoc| {assoc => relation} }
-      all.includes(includes).order('quantities.lft').each do |i|
-        item_type[:associations].inject(i) { |o, m| o.send(m) }.each do |s|
-          subitem_value =
-            if i.respond_to?(item_type[:value_field])
-              s_value = s.send(item_type[:value_field])
-              i_value = i.send(item_type[:value_field])
-              # NOTE: for now scaling is designed only for Ingredients
-              s_value * i_value / i.food.ref_amount
-            else
-              s.send(item_type[:value_field])
-            end
+      all.subitems.order('quantities.lft').each do |i|
+        i.subitems.each do |s|
+          subitem_value = i.respond_to?(:amount) ? i.amount*s.amount/s.ref_amount : s.value
           subitems[s.quantity][i] = [subitem_value, s.unit]
         end
       end