The #1 Fat to Avoid: Artificial Trans Fats
Artificial trans fats are a complete no-go for anyone focused on health, and especially for those on a ketogenic diet. These fats are created through a process called hydrogenation, which adds hydrogen to liquid unsaturated fats to make them solid at room temperature. The resulting "partially hydrogenated oils" are cheap and extend shelf life, making them popular in processed foods.
However, artificial trans fats are the worst type of fat for your health. They have been shown to raise LDL ("bad") cholesterol while lowering HDL ("good") cholesterol, significantly increasing the risk of heart disease, stroke, and type 2 diabetes.
Where to find artificial trans fats:
- Processed baked goods: Cookies, cakes, pies, and biscuits frequently contain these fats.
- Margarine and vegetable shortening: These were created specifically to be shelf-stable, containing high levels of partially hydrogenated oils.
- Fried foods: Many restaurants use partially hydrogenated oils for deep-frying, and repeated heating can increase the trans fat content.
- Packaged snacks: Crackers, microwave popcorn, and certain candy bars often include these harmful fats.
The Problem with Processed Vegetable and Seed Oils
Not all plant-based oils are healthy, and many commonly used vegetable and seed oils should be avoided on a keto diet. Highly processed oils like canola, corn, soybean, and regular sunflower oil undergo intensive processing involving high heat, which can damage the fat and create inflammatory free radicals.
These oils are also very high in omega-6 fatty acids, which are beneficial in small amounts but can promote chronic inflammation when consumed in excess. Most modern diets have a skewed omega-6 to omega-3 ratio, which is linked to an increased risk of inflammatory diseases. For optimal health, you should focus on balancing these essential fatty acids by consuming more omega-3s and fewer omega-6s.
American Heart Association guidance on fats
Fried Foods and "Dirty Keto" Fats
Even if cooked in what you believe is a healthier oil, deep-frying can damage fats due to the high temperatures involved. Furthermore, many establishments and packaged food producers use the very processed, high omega-6 oils mentioned earlier. This process generates harmful compounds and increases the inflammatory load on your body.
Moreover, the concept of a "dirty keto" diet, which focuses solely on macros without regard for food quality, often leads to excessive consumption of processed and fried items. These foods, including processed meats like hot dogs, sausages, and cured deli meats, can contain high amounts of unhealthy fats, sodium, and additives. For a truly healthy ketogenic lifestyle, focus on whole, minimally processed ingredients.
Healthy Fats vs. Unhealthy Fats: A Comparison
| Fat Type | Examples to Avoid | Examples to Embrace | Reason |
|---|---|---|---|
| Artificial Trans Fats | Margarine, vegetable shortening, fried fast food, most baked goods | None. Should be completely avoided. | Increase "bad" LDL cholesterol, promote inflammation, high risk of heart disease. |
| Processed Seed Oils | Canola, corn, soybean, regular sunflower/safflower oil | Extra virgin olive oil, avocado oil, high-oleic sunflower/safflower oil | High omega-6 content; prone to oxidation and inflammation when processed or heated. |
| Saturated Fats | Low-quality, processed meats, excessive consumption from any source | High-quality, grass-fed butter/ghee, fatty fish, quality red meat in moderation | Quality and source are key. Older science demonized all saturated fat, but newer data shows nuance, especially with high-quality sources in moderation. |
| Processed Meats | Hot dogs, sausages, cured deli meats | Fresh, whole meats (grass-fed preferred) | Often contain unhealthy fats, additives, and are linked with health risks. |
Nuance on Saturated Fats
Historically, saturated fats were broadly condemned and linked to heart disease. This led to the rise of processed alternatives like margarine. However, modern understanding has shown this view to be overly simplistic. The quality and source of saturated fat are more important than the fat type alone. Grass-fed butter, ghee, and fatty fish are all sources of saturated fat, but they come in a whole-food package with other nutrients. The key is moderation and balance. Emphasizing healthy unsaturated fats, while consuming high-quality saturated fats, is a balanced approach.
How to Choose the Right Fats for Your Keto Diet
To maximize the health benefits of your ketogenic diet, focus on whole food sources and high-quality oils. Here is a list of fats to embrace:
- Avocados and avocado oil: Rich in monounsaturated fats, fiber, and nutrients.
- Olives and olive oil: Extra virgin olive oil is loaded with antioxidants and monounsaturated fat.
- Nuts and seeds: Excellent sources of healthy fats, fiber, and protein. Good choices include macadamia nuts, almonds, walnuts, chia seeds, and flax seeds.
- Fatty fish: Salmon, mackerel, and sardines are packed with anti-inflammatory omega-3s.
- Grass-fed butter and ghee: Better sourced dairy fats can provide beneficial fatty acids like butyrate.
- MCT oil: Derived from coconut, MCTs are easily converted into ketones for quick energy.
- Tallow and lard: High-quality animal fats, preferably from pasture-raised animals, are stable for cooking at high temperatures.
Conclusion: Prioritizing Quality Fats
While the ketogenic diet requires a high intake of fat, it is crucial to recognize that not all fats are created equal. Avoiding artificial trans fats and highly processed seed and vegetable oils is the most important step. Prioritizing fat from high-quality, minimally processed sources like whole foods and specific, stable oils will ensure that your ketogenic diet is not only effective for weight loss but also beneficial for your long-term health. By focusing on quality over quantity, you can avoid the common pitfalls of a "dirty keto" diet and reap the full spectrum of advantages from a clean, high-fat lifestyle.
