Make small diagonal slashes on the skin side of the mackerel - don't cut too deep. The ketogenic diet (or keto for short), is a popular diet with many people successfully losing weight. It is one of the most nutritious foods on the planet! In this blog post I’ll be sharing a complete ALDI Keto List of must have low carb foods that you can keep an eye out for the next time you’re at the budget supermarket. Fatty fish like salmon, sardines, and mackerel are very high in omega-3 fats, which are very beneficial for lowering insulin levels. Sardines, Mackerel, Anchovies, and other Canned Fish. Our keto rating system ranks foods based on ingredients, net carbs, and fat content. LIDL Keto Shopping List.