Many of you will recognize "eat real food, not too much and mostly plants" comes from Michael Pollan.
I highly recommend any and all of his books, but would especially encourage you to check out "In Defense of Food".
Let's start with the first principle: Eat Real Food
Avoid packaged foods
Real food is food that your great grandmother would recognize. Packaged foods are a problem. Many (most) contain ingredients that have nothing to do with nutrition: preservatives, taste and texture enhancers. A good rule of thumb is to avoid anything with more than 5 ingredients or with any ingredient that you don't recognize as food. Another helpful hint is that real food is mostly found around the perimeter. Packaged foods are also high in refined processed carbohydrates which will spike insulin levels, cause chronic low grade inflammation and lead to weight gain.
Avoid refined carbohydrates
Refined carbohydrates have become a mainstay in Western diets and their increased consumption is thought to be at the core of the diabetes and chronic disease epidemic in our society. Refined carbohydrates are forms of sugars and starches that do not exist in nature. They have been processed, extracted, concentrated, purified or transformed enzymatically from natural whole foods. Refined sugars make packaged goods sweeter. Over the past 30 years, the low fat diet trend has resulted in foods where fat has been removed and substituted with added refined sugars. Refined grains are whole grains that have been broken down to some extent through grinding, polishing, high-heat treatment and extrusion puffing. The extent of processing can vary from minimal (cracked and stone-ground grains) all the way to fine powders, flours and starches. With processing the outer bran coating is lost and with it fibre and many nutrients. The net result is that refined grains are easily and rapidly digested, converted into sugars and absorbed into the blood stream and resulting in the release of insulin to maintain controlled blood sugar levels. The more sugars absorbed the more insulin is released, and high levels of insulin over time result in increased inflammation, weight gain, and insulin resistance, eventually (potentially) descending into type II diabetes and metabolic syndrome.
A good rule of thumb is to balance your fats:
From a practical stand-point this means getting a mix of fats from whole, unprocessed, high quality foods - nuts, seeds, fish, pasture raised, grass fed animals, eggs, butter, olives avocado and coconut.
One of the reasons many people overeat is that they eat too quickly. The reason this happens your body needs time to send signals to your brain that you are full and to give you a feeling of satiation. There is a complex web of signals that send information from your stomach and intestine via stretch receptors and hormones like cholecystokinin and leptin, to your brain where the release of dopamine signals pleasure after eating. In addition to helping avoid overeating, eating slowly improves your digestion. More time chewing your food allows amylase in your saliva more time to break down starches into simple sugars, the sugars make the food taste sweeter and richer which leads towards satiation. The more salivary amylase released the higher the pre-absorptive insulin response which seems to smooth out the overall insulin response to carbohydrates.
Eat to 80% full
This rule again probably works because of the lag between food passing through the stomach and small intestine and the brain's signalling satiation. Put another way, when eating, your brain is probably 15 to 20 minutes behind your stomach, so when you feel 80% full you have probably eaten enough. Eat to 100% and you have probably overeaten. Okinawans are renowned for longevity call this "Hara Hachi Bu" which seems to be one of their keys to staying lean and healthy into advanced ages.
Fasting, Intermittent Fasting or Time Restricted Eating
Whether is is prolonged fasting (nothing but water for >1-5 days), intermittent fasting (18-24 hours) or time restricted eating (consuming all calories within an 8 to 12 hour per day window) there is increasing evidence that the body responds well to time without nutrients.
All of these strategies have been shown to improve multiple risk factors for diabetes, metabolic syndrome, heart disease, cancer and neurodegenerative disease (Mattson et al., 2014). Although the mechanisms of action are not completely understood, fasting appears to promote coordinated positive effects on the aging process. I will spend more time on this in a future blog post, but the point here is that building a regular fasting period into your weekly or daily eating patterns can have profoundly positive health effects.
For some this will be the hardest principle to accept, so I am going to focus mainly on why plants are healthy and more of them is always good before concluding with some of the evidence regarding a pure plant-based diets.
Simply put, eating a variety of fruits and vegetables (>5 portions per day) is the best way to get all the micronutrients that your body needs.
In addition to being rich sources for vitamins and minerals, plants also contain anti-oxidants and many other beneficial compounds that we are only now beginning to appreciate the importance of. For vegans, there are considerations around supplementing Vitamin B12, Vitamin D and Omega 3 fatty acids.
Dietary fibre is found mainly in fruits, vegetables, whole grains and legumes and is probably thought of most in connection with preventing constipation, but fibre has many other benefits to good health.
Fibre comes from the roughage of plant foods - the bulk that your body cannot digest or absorb.
There are two types of fibre - soluble fibre that dissolves in water and has been shown to lower blood glucose and cholesterol; and insoluble fibre that increases the bulk and promotes the movement of stool through the bowels.
Fibre also promotes diversity in the microbiome that has been associated with reduced inflammation, chronic disease and optimal weight.
Researchers have shown that a more plant-based diet may help prevent, treat, or reverse some of our leading causes of death, including heart disease, type 2 diabetes, and high blood pressure.
Evidence of the benefits of plant-based diets by category (The Plantrician Project)
An update of the evidence relating to plant-based diets and cardiovascular disease, type 2 diabetes and overweight
Not all plant-based diets are created equal
Dr. Brendan Byrne