diff --git a/net/food_net.py b/net/food_net.py
index cdafcdd..30bac5c 100644
--- a/net/food_net.py
+++ b/net/food_net.py
@@ -97,11 +97,16 @@ class FoodCNN(nn.Module):
         
         return x
     
-    def forward(self, x):
-        # 如果启用内部预处理且输入是tensor
-        if self.use_internal_preprocess and isinstance(x, torch.Tensor):
-            x = self.internal_preprocess(x)
+    def _forward_network(self, x):
+        """
+        网络的核心前向传播（不包含预处理）
         
+        Args:
+            x: 预处理后的tensor，形状为 [batch, 3, 32, 32]
+            
+        Returns:
+            torch.Tensor: 模型输出
+        """
         # 第一个卷积块
         x = F.relu(self.conv1(x))
         x = F.relu(self.conv2(x))
@@ -130,6 +135,13 @@ class FoodCNN(nn.Module):
         
         return x
     
+    def forward(self, x):
+        # 如果启用内部预处理且输入是tensor
+        if self.use_internal_preprocess and isinstance(x, torch.Tensor):
+            x = self.internal_preprocess(x)
+        
+        return self._forward_network(x)
+    
     def forward_mobile(self, x):
         """
         移动端前向传播（包含预处理）
@@ -143,8 +155,8 @@ class FoodCNN(nn.Module):
         # 移动端预处理
         x = self.mobile_preprocess(x)
         
-        # 标准前向传播
-        return self.forward(x)
+        # 执行网络前向传播
+        return self._forward_network(x)
 
 
 def create_food_cnn(use_internal_preprocess=False):