Fat loss is an emotional issue, complicated by body image issues, conflicting advice re: what works and what is healthful, and unrealistic media images of digitally altered bodies. Too often, the focus is on the end (losing fat), and not the means (changing habits). This doesn’t work because there is no end to weight issues until you’re dead. Unless a fat loss plan is the result of permanent behavioral change, the fat will come right back.
I’ve written about my own personal changes in body composition and metabolism here. During the years I was suffering from asthma symptoms, I read constantly and obsessively about human physiology in an all-out effort to find a way to cure myself and breathe normally again. I eventually succeeded, and on the way learned a thing or two about inflammation, metabolism, digestion, immunity, gut flora, mitochondria, and other factors that can influence body composition. Since so many people are interested in getting a bit leaner, I’ve attempted to synthesize what I’ve learned in this area in an easily digestible format, in this post.
The problem with most fat loss plans is that they require too much willpower to sustain on a long-term basis. Approaches that are harder to make work include:
- calorie counting with calorie restriction to the point of near-constant hunger
- extreme exercise regimens that stretch the body’s ability to naturally and easily recover
- “bizarro” or fad-diets with many difficult-to-remember rules that must be strictly followed (and often make socializing difficult or awkward)
Long-term fat loss can only be achieved with long-term behavioral change. Behavioral change that requires a large expenditure of willpower is difficult to maintain.
An easier, more effective approach is to shift habits in a direction that encourages consistent fat loss (or maintains a favorable body fat percentage).
But how do we know which habits to change?
In this post I’ll look at five physiological mechanisms that trigger fat-loss, and highlight some simple, easy behavioral changes that are related to each of the five triggers.
1. Increase Insulin Sensitivity and Reduce Circulating Insulin
Insulin is a hormone secreted by the pancreas that functions to regulate blood sugar. Insulin shuttles glucose from the bloodstream into muscle cells, fat cells, and the liver. If blood sugar levels are constantly elevated due to a high carbohydrate diet and/or low levels of physical activity, the pancreas will need to secrete more insulin, more frequently, to keep blood sugar levels from getting too high. This can lead to a condition called insulin resistance, and eventually metabolic syndrome, type 2 diabetes, and cardiovascular disease.
Circulating insulin prevents the release of glucagon, another hormone secreted by the pancreas that converts stored glycogen and body fat into glucose. Even if you have normal insulin sensitivity, constant snacking throughout the day will prevent glucagon release, thus preventing the use of stored fuel.
How can you increase insulin sensitivity and reduce circulating insulin?
- Don’t consume food or beverages that spike blood sugar (soda, candy, juice, dried fruit, or large amounts of bread, pizza, rice, pasta, potatoes, and other carbohydrates).
- Don’t snack between meals.
- Take supplements that have been demonstrated to increase insulin sensitivity (including chromium picolinate, alpha-lipoic acid, and biotin)
2. Increase Leptin Sensitivity
Leptin is a protein synthesized in fat cells. Under normal conditions, leptin functions to reduce appetite.
Leptin resistance can occur in cases of obesity, or in cases where there is unlimited access to high palatable, energy dense foods.
Since leptin levels are related to total body fat, losing body fat can lead to less leptin secretion, increased leptin sensitivity, and reduced appetite (cascading fat loss).
How can you increase leptin sensitivity?
- Reduce body fat until leptin sensitivity is regained
- Don’t consume foods and beverages that have artificially enhanced palatability (added salt, sugar, and MSG).
- Eliminate high-fructose corn syrup
3. Increase Circulating Growth Hormone
Growth hormone (GH) is secreted by the pituitary gland, and gradually tapers off as we age. In adults, growth hormone is responsible for cell regeneration, muscle growth, lipolysis (fat burning), bone density, and many other functions. Too little growth hormone is related to obesity.
Growth hormone is released during deep sleep, in response to intense exercise, and in response to fasting (so that the body can burn fat for fuel). Growth hormone released is blocked by high glycemic meals (meals that are high in sugars and/or starches), as well as alcohol.
I’ve written an earlier post about how to naturally stimulate growth hormone release.
How can you naturally encourage growth hormone release?
- do short bouts of very intense exercise multiple times a week
- eat mostly low-glycemic load meals (low in total carbohydrate)
- fast for 16 or more hours at least once a week (no food until mid afternoon, or skip dinner)
- turn the lights off early in the evening (including all screens) to encourage going to sleep earlier
- reduce alcohol to a drink a day or less
4. Increase Brown Adipose Tissue (Brown Fat) Activity
Brown fat is a type of fat that generates heat. It is higher in mitochondria and capillaries (as it requires more oxygen). The physiological function of brown fat is to produce heat in mammals that are incapable of shivering (including newborns, and hibernating animals).
Until recently, it was thought that brown fat disappeared in adult humans. Recent studies using PET scans have shown that adults do retain some brown fat in the neck and upper chest area.
Brown fat may aid in overall fat loss, as it converts excess calories into heat. Cold exposure increases metabolic activity in brown fat.
Most adults have some brown fat, but this percentage drops among the obese.
Does consistent cold exposure increase brown fat levels and activity, and reduce obesity? There are many anecdotal reports that it does, but there is not enough research to answer this question definitively. How much cold exposure is necessary? How often? Mark Sisson has a good post in which he speculates on the answers to these questions, and suggests personal experimentation.
How can we (possibly) increase brown fat activity, thus improving our metabolic profile and turning excess calories into heat?
- take cool or cold showers (or baths)
- reduce the use of central heating (especially at night)
- exercise in cool or cold weather
5. Maintain a Healthy Gut Microbiome
The bacteria that live in our digestive tract (up to hundreds of different species) have a profound effect on our health, influencing our immune system, inflammation levels, vulnerability to cancer, production of vitamins, and obesity.
Startlingly, the gut communicates with the brain via the vagus nerve, influencing factors such as appetite and the response to stress.
Though there are hundreds of different species that inhabit our gut, there are a limited number of enterotypes (a gut microbiome dominated by a few main types of bacteria). These types are influenced both by colonization (which bacteria you are exposed to as an infant), and by diet (the food you eat provides food that is more favorable to some bacteria species, and less favorable to others).
Some studies have shown that the bacteroides enterotype is associated with reduced obesity (at least in relation to the number of firmicutes class of bacteria).
The bacteroides tend to be associated with diets higher in animal protein and saturated fat. Other beneficial bacteria thrive off non-digestible food components called fructooligosaccharides (there’s a Scrabble word). Foods fermented with various strains of lactobacillus may provide protection against certain kinds of cancer and inflammation.
How can you encourage a healthful gut microbiome that will improve general health and may lead to reduced appetite and weight loss?
- eat a high quantity of fruits and vegetables
- include some animal protein and saturated fat in your diet
- eat fermented probiotic foods (like raw sauerkraut)
- avoid using oral antibiotics unless absolutely necessary
- avoid or greatly reduce intake of refined carbohydrates
This doesn’t cover everything. Other things to consider are:
- reducing intake of chemicals that contribute to weight gain (bisphenol-A, artificial sweeteners)
- reducing exposure to botanical estrogen mimics (tea tree oil, lavender)
- reducing cortisol levels via stress reduction and meditation
- emotional relationship with eating, eating as addiction, learning how to feel good and induce pleasure without food
- obesity as a result of childhood abuse (and effective therapeutic approaches)
Though many of the recommendations in this post are in line with a more paleolithic diet and lifestyle, I believe there are many possible healthful lifestyles (including, for some, vegetarianism). Every person has to find their own way based on their genetic makeup, personal beliefs, cultural background, and empirical observations.
For more detailed discussions of weight-loss and recommendations, including developing a personal weight-loss system, I recommend Dan’s Plan (not a paid endorsement, but Dan is a personal friend, and the most knowledgeable person I know regarding the physiology of weight-loss).