Feeling well all day is a constant dance between activity, what you eat and stress reduction. In the last 30 years, we have looked at these areas in isolation without success. We are losing ground in the nation's battle on obesity despite expensive government campaigns, improved nutritional labeling and an increasing public awareness of our expanding waist lines. Conventional wisdom has targeted "eat less," "reduce your fat intake," "exercise more" and "deprive yourself of the things you enjoy." Unfortunately there is no evidence that these methods work for sustainable weight reduction.
The "exercise" part of this is helpful for health outcomes independent of weight as long as it is sustainable, fun and does not add another stress to the day. Excess stress can have negative affects on other health parameters such as overeating, mood or fatigue.
Now to some basic science of how we fuel our engines (the muscles). It is not as simple as "calories in and calories out." Fat tissue is living and dynamic with fatty acids constantly flowing in and out of fat tissue, like a bank account. We gain body fat when we deposit more than we withdraw. This process is mostly controlled by hormones- predominantly insulin in partnership with lipoprotein lipase (LPL) and Human Growth Hormone (HGH).
Carbohydrates are the primary fuel for muscles and the most accessible, stored in the muscle itself. Fat tissue can provide a supply of fatty acids to fuel the muscle (like a reserve tank) but the process is slower as they must be released from the fat cells first. The factories in the muscles to burn the fuel (carbohydrate and fat) are the mitochondria.
The role of insulin:
When glucose is ingested we release insulin, which removes glucose from the blood and stores it either as fat or carbohydrate. So you are now making deposits into the fat account. Exercise increases the sensitivity on muscle receptors, which makes it more likely that glucose will be stored in the muscles and less likely that it will be stored as fat. Insulin inhibitsrelease of fat from fat cells. Easy to moderate exercise encourages the fatty acid release. When fasting (even over night) and insulin is low, fat provides almost all of our energy from the release of fatty acids from the fat tissue. In summary insulin promotes deposits into the account. Exercise and low insulin states enhance withdraws.
Now let's discuss the storage and release process of fatty acids from the fat cells. Fat is stored in adipose tissue as triglycerides (3 fatty acids on a glycerol backbone). Triglycerides in fat cells come from dietary fat and from carbohydrates (converted in the liver to triglycerides). Triglycerides are too large to pass through the fat cell membrane and must be broken down to free fatty acids first to exit (withdraw).
Inside fat cells, triglycerides are continuously broken down and repackaged. Fatty acids not immediately repackaged will escape into the bloodstream. Fatty acids in the blood will be used for fuel and the rest converted to back to triglycerides by the liver, loaded on VLDL and shipped back to fat cells.
What controls this cycle? Blood sugar.
The byproduct of burning glucose is glycerol phosphate which provides the glycerol molecule for triglycerides. So eating excess carbs increases glucose and glycerol phosphate, which increases triglycerides, which under the influence of insulin fattens us.
In a low insulin environment, as blood sugar decreases, fatty acids are released to compensate (make up the balance) and muscle cells burn less glucose in favor of fatty acids.
In a high insulin environment, as blood sugar increases fatty acids are bound up in fat cells and we rely more on glucose for fuel. Then the blood sugar levels drop, we cannot mobilize the fat and we perceive hunger. So in reality you get hungry because you have too much fat and insulin, and the perception that people get fat because they have gluttony is not true! Insulin is the master control of fat metabolism and fat tissue is very sensitive to insulin; even trace amounts.
What is Lipoprotein Lipase (LPL) and why do we care?
LPL is the gatekeeper of fat absorption into cells. LPL is regulated by insulin, which increases LPL activity in fat tissue and decreases it in muscles. With the help of LPL, high insulin levels promote fat storage as muscles burn glucose.
LPL is more active in certain tissues genetically, this is why men may acquire a "beer belly" and women place more weight on the thighs. Calorie-restriction also increases LPL activity in fat tissue and decreases it in muscles, resisting fat loss and making the weight regain occur once the carbs are added back in. This is why the semi starvation diets often fail in the long term.
Exercise is your friend- increasing LPL activity in muscles during activity (assisting fat burning); but afterward LPL increases it in fat tissue making the body want to restock whatever fat it surrendered. Carbs and insulin increase LPL in fat tissues; fats and protein do not. So if you are an exerciser and want to reduce fat- be wary of the cycle of work out, get hungry, eat more carbs and refill the fat stores.
A note on insulin resistance and diabetes: fat tissues are extremely sensitive to insulin, much more than muscle. Muscles become insulin resistant long before fat cells do. So as extra insulin is secreted to compensating for muscle's resistance, one becomes more fat and the cycle escalates. The same can be seen with aggressive insulin therapy to treat diabetes, almost all will gain weight as a result.
A few extra benefits of exercise:
Exercise over the long haul up-regulates the enzymes of the fat oxidation pathways, more mitochondria (factories) and capillaries (roads) to allow fat burning all day. Human growth hormone (HGH) is produced to help release free fatty acids from fat storage into the bloodstream where they may be burned.
So here is you upgrade plan for spring:
- Avoid all simple carbs (sweets, fluffy white refined grains, sugary drinks) if trying to reduce weight.
- Minimal simple carbs to maintain weight.
- Make most grains whole grains - aim for > 3 gm fiber/serving
- Eat 2 times as much complex plant carbs (leafy greens, rainbow colored fruit and veggies) as fats and proteins
- Avoid "fast fat" (trans fat in fried and processed foods).
- Some cheese, low fat dairy and other animal fats- less if trying to lose weight.
- Eat more healthy fats (like nuts, seeds, olive oil, avocados, cold water fish).
- Avoid highly processed and salted meats.
- Some eggs, fish, lean meats and poultry
- More vegetable proteins (nuts, seeds and legumes).
CORRECT YOUR APPETITE
- Happens as a result of the above conscious actions. Your body is now supplying fuel from your fat and does not need the extra added carb fuel.
- Be patient and listen to your bodies true signals.
- Do not go hungry. Eat a lean healthy fat with protein if trying to lose weight.
- Eat healthy fat and protein for breakfast.
- "Play is the process, fitness is the product"- Dr. George Sheehan 1975