WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
The idea that a low-fat diet is the answer if you struggle with weight gain and/or have risk factors for heart disease is a persistent one. For the past 50 years, obesity and heart disease have steadily risen. The question is why? Are dietary fats really to blame?
And if they are, which fats gave rise to these problems? It's unfortunate, but researchers have frequently failed to take into account the fact that not all fats are created equal. Some do harm, while others are vitally important for optimal health.
Even more tragic, harmful and beneficial fats have been confused, leading to a situation where people are encouraged to eat the unhealthy ones and avoid the beneficial ones.
In more recent years, a number of scientists have stepped forward to promote a healthier view of dietary fats. But trying to change public policy is a difficult task that often takes one or more decades.
Anti-Obesity Campaigners Urge Britons to Ditch Low-Fat Diets
The British National Obesity Forum (NOF) and Public Health Collaboration (PHC) report on obesity is a perfect example. The report, which is based on the analysis of 43 studies, warn that the policy to encourage people to eat a low-fat diet is having a "disastrous impact on health."1,2
Calling for an overhaul of official dietary guidelines, which they claim are based on flawed science that has resulted in higher consumption of net carbs and junk food, the report notes that eating healthy fat does not make you fat. According to Reuters:3
"The NOF/PHC report, entitled 'Eat Fat, Cut The Carbs and Avoid Snacking To Reverse Obesity and Type 2 Diabetes' ... said snacking in-between meals is what is making people overweight.
'The role of poor dietary advice has been ignored for too long. Specifically, the 'low fat' and 'lower cholesterol' messages have had unintended disastrous health consequences,' the report said."
According to NOF chairman Dr. David Haslam:4
"As a clinician treating patients all day every day, I quickly realized that guidelines from on high suggesting high carbohydrate, low-fat diets were the universal panacea, were deeply flawed.
Current efforts have failed, the proof being that obesity levels are higher than they have ever been, and show no chance of reducing despite the best efforts of government and scientists."
Key Findings
The key findings of the NOF/PHC report include the following:
✓ Eating fat does not make you fat
High-fat, low-net-carb diets are superior to low-fat, high-net-carb diets for weight loss and heart health. |
✓ Calorie counting doesn't work
Calories are not created equal. They have differing metabolic effects depending on their source, so counting calories is useless for successful weight loss. |
✓ You cannot outrun a poor diet
Obesity cannot be conquered simply by increasing exercise as obesity is rooted in metabolic dysfunction that leads to abnormal energy partitioning. |
✓ Saturated fat does not cause heart disease
Saturated fat and cholesterol has little to do with the development of heart disease, and a new analysis of evidence from 40 years ago does not support restricting saturated fat.
One of the original researchers was Ancel Keys, Ph.D. — the man who initially proposed the link between saturated fat and heart disease — and it's believed he was largely responsible for suppressing these damning findings, as they don't support his original hypothesis. Only parts of the trial's results were ever published, leaving out the controversial finding that replacing saturated fats with vegetable oil had NO benefit on mortality. While vegetable oils lowered total cholesterol levels by 14 percent after one year, this did NOT result in improved health and longevity, which is the conventional belief.
Instead, the research showed that the lower the cholesterol, the higher the risk of dying.
For every 30-point drop in total cholesterol there was a 22 percent increased chance of death. In the 65 and older category, those who received vegetable oil experienced roughly 15 percent more deaths compared to seniors in the saturated fat group.
The vegetable oil also did not result in fewer cases of atherosclerosis or heart attacks.
On the contrary, autopsies revealed that while both groups had similar levels of arterial plaque, 41 percent of the vegetable oil group showed signs of at least one heart attack compared to just 22 percent of those in the saturated fat group.5,6,7,8,9,10,11,12 |
✓ Avoid foods labeled "low-fat" or "low cholesterol"
There's no evidence to suggest avoiding saturated fat or dietary cholesterol reduces heart disease or death from heart disease. |
✓ Meal frequency influences your weight
Excessive snacking is a significant contributing factor to obesity. To lose weight, you need to reduce your meal frequency. I recommend limiting it to two meals per day, either breakfast/lunch or lunch/dinner, within a six- to eight-hour window each day. It's also beneficial to avoid eating at least three hours before bedtime to protect your mitochondrial function. |
✓ Commercial influences have corrupted public dietary guidelines
The report accuses the food and beverage industries of manipulating public health organizations and corrupting the dietary guidelines for commercial gain. |
Why Public Policy Is so Hard to Change
As in the United States, the U.K. encourages people to eat high amounts of carbohydrates. While high-fiber carbs like vegetables are important for good health, net carbs (total carbs minus fiber; think sugars and starches) really need to be restricted if you want to optimize your health and weight.
The report has not been well received, however. Public Health England's (PHE) chief nutritionist, Alison Tedstone, Ph.D., called the recommendation to eat a high-fat, low-net-carb diet "irresponsible and potentially deadly," while Associate Medical Director for the British Heart Foundation (BHF), Dr. Mike Knapton, said the report was "full of ideas and opinions."13,14
The U.K.'s Royal Society for Public Health (RSPH) called the report "a muddled manifesto of sweeping statements, generalizations and speculation,"15 and the British Association for the Study of Obesity (ASO) has gone on record saying it "does not endorse the content of the report as it contradicts current evidence ... "16
This kind of backlash is to be expected. Rarely if ever is it quick or easy to make course corrections in public policy.
The problem stems from the fact that careers are invested in certain recommendations. Not to mention the fact that government organizations can rarely afford to admit they were wrong, since public trust is at stake. Industry interests are also at play.
Today's diet is a boon to the food industry, as the primary ingredients are far cheaper to produce and have a far greater profit margin than nutrient-dense whole foods. My recent interview with British cardiologist Dr. Aseem Malhotra addresses some of these concerns.
Healthy Dietary Fats Actually Promote Burning of Body Fat
Your body can use both carbs and fat for fuel, but they're in no way equal. When your body burns glucose as its primary fuel, it actually inhibits your body's ability to access and burn body fat. With an ever-present supply of carbs, your liver downregulates the entire fat burning process because it's not needed.
So, if you eat the standard American diet, chances are you've radically reduced your ability to burn body fat for fuel. How do you rev up your body's fat-burning engine? Part of the equation is to eat more healthy dietary fats. The other part of the equation is to limit net carbs. Fat is a far preferable fuel for your body as it burns far more efficiently and "cleaner" than carbs.
To effectively burn body fat, you may need as much as 50 to 85 percent of your daily calories to come from beneficial monosaturated and saturated fats, which include:
✓ Olives and olive oil (make sure it's third party-certified, as 80 percent of olive oils are adulterated with vegetable oils. Also avoid cooking with olive oil. Use it cold.) | ✓ Coconuts and coconut oil (excellent for cooking as it can withstand higher temperatures without oxidizing) | ✓ Butter made from raw grass-fed organic milk |
✓ Raw nuts, such as macadamia and pecans | ✓ Seeds like black sesame, cumin, pumpkin and hemp seeds | ✓ Avocados |
✓ Grass-fed meats | ✓ Lard and tallow (excellent for cooking) | ✓ Ghee (clarified butter) |
✓ Raw cacao butter | ✓ Organic-pastured egg yolks | ✓ Animal-based omega-3 fat such as krill oil and small fatty fish like sardines and anchovies |
So, while it may sound ironic, eating more fat and fewer net carbs will ultimately help your body to burn more fat. There are other methods that can help you switch over to fat-burning mode too. One reason so many struggle with their weight (aside from eating processed foods in lieu of real foods) is because they rarely if ever skip a meal.
As a result, their bodies have adapted to burning sugar as the primary fuel, which down-regulates enzymes that utilize and burn stored fat. Intermittent fasting can change that. By abstaining from food, your liver runs out of glycogen and then, just like that, starts to use up glycogen stored in your body.
Harmful Dietary Fats to Avoid
Fats can be harmful, but it's important to be specific. For an in-depth review of dietary fats, please see the Weston A. Price Foundation's article, "Saturated Fat Does a Body Good."17 In summary, harmful fats that contribute to heart disease are primarily:
1. Trans fats. By acting as a pro-oxidant, trans fat contributes to oxidative stress that causes cellular damage.
2. Highly refined polyunsaturated vegetable oils (PUFAs, such as peanut, corn and soy oil), which are high in damaged omega-6 and produce toxic oxidation products like cyclic aldehydes when heated.
These oils promote oxidized cholesterol, which becomes destructive when entering into your LDL particles. Additionally, omega-6 polyunsaturated fats, when taken in large amounts, cannot be burned for fuel. Instead, they're incorporated into cellular and mitochondrial membranes where they are highly susceptible to oxidative damage, which damages the metabolic machinery.
To protect your mitochondrial function, limit PUFAs to less than 10 percent of your daily calories. At higher levels, you will increase the PUFAs concentration in the inner mitochondrial membrane, which makes it far more susceptible to oxidative damage. Also avoid exceeding 5 percent of your daily calories as omega-6 fats.
In comparison, healthy saturated fats such as those found in animal products and coconut oil:
- Increase your large, fluffy LDL particles that are NOT associated with an increased risk of heart disease.
- Increase your HDL levels, which is associated with lower heart disease risk. This also compensates for any increase in LDL.
- Do NOT cause heart disease as made clear in a large number of studies.18,19,20,21,22,23
- Do not damage as easily as other fats because they do not have double bonds that can be damaged through oxidation.
- Serves as a "clean-burning fuel" for your brain and mitochondria, producing far less damaging free radicals than sugars and non-fiber carbs.
Diets High in Healthy Fats and Low in Net Carbs Solve Several Problems
Mounting evidence suggests high-fat, low net-carb diets may be the key that many people have been looking for, as it solves more than one problem. Not only does it help you shed excess body fat, it does so while improving metabolism, boosting overall energy levels, lowering inflammation, promoting optimal health and maximizing longevity in a number of different ways. One effective way to optimize your fat-burning system is to:
- Limit your net carbs (total carbs minus fiber) to a maximum of 30 to 40 grams per day. You can consume as many high-fiber veggies as you like. They're carbs, but since they're high in fiber, they're typically quite low in net carbs.
- Limit protein to a maximum of 1 gram of protein per kilogram of lean body mass.
- Increase your intake of healthy fats to 50 to 85 percent of your daily calories.
As mentioned, you can kick the entire process up a notch by implementing intermittent fasting, at least for a finite period of time while your body returns to a balanced state. After that, assuming you're still eating right, you'll only need to intermittent fast on a maintenance basis. The fear of healthy dietary fat is actually part of why we're currently struggling with obesity, diabetes, and heart disease of epidemic proportions.