How reducing eating?
Some important questions arise soon or later in the life. One of this is the following: when should I eat and when should I stop eating? Should I just follow my hunger?
In the developing age, my parents pushed me (when not obliged me) to eat regularly in the scheduled hours of the day (breakfast, lunch and some snack before dinner) whatever they liked, because I had to grow up and I needed nutrients for that. God bless them!
However, our developing speed slows down while growing up and we began to gain weight without changing our life style and diet. Some people are lucky because they are fast metabolizer and rarely gain weight. Others are slow metabolizer and are more prone to gain weight.
Obviously, this is not a standard, but a good representation of what happened to me and what happens to many people: they discover themselves overweight in the late developing age or early adulthood. In this age we are still under the power of two major conditioning factors: the hedonism associated with foods intake and our parents’ life-style built in us.
Are you still thinking that you need all those calories?
Did you ever think to change the amount of calories in your diet (actually diminish that amount!), without thinking that you are going to eat less than you need? A right diet for your body and mind balances everything: energy, weight, nutrients, and other foods’ components that do not yet have labels or a chemical formula in the nutrition facts.
A molecular view
Everything is a chemical! I will repeat here that some studies have suggested that an increased production of ghrelin may enhance appetite evoked by the sight of food, while an increase in stress may also influence the hormone's production. These findings may help to explain why hunger can prevail even in stressful situations.
Wealth of data indicates that 5-HT2C receptor (serotonin receptor) activation regulates appetite and food consumption, probably by promoting satiety. Given this appetite suppression by activation of 5-HT2C, selective agents with high affinity for this receptor over 5-HT2B and 5-HT2A are being developed for the treatment of obesity. For this purpose, Lorcaserin is the only agent that has completed phase III in clinical trials, and has been approved by the FDA. Previous agents have all been removed from the U.S market.
The 5-HT2C receptors are coupled to phospholipase C (PLC) via Gαq and phospholipase A2 (PLA2), possibly via Gα13. PLC metabolizes phosphatidylinositol 4,5-bisphosphate into inositol 1,4,5-triphosphate (IP3) which regulates cellular Ca2+ flux by binding to IP3 receptors and induces the release of Ca2+. In addition, the activation of PLA2 also recruits a RhoA/PLD pathway through RhoA, an enzyme that regulates a wide spectrum of cellular functions through PLD (phospholipase D) target protein, such as transformation and cytoskeletal reorganization. The 5-HT2C receptors are also capable of stimulating the extracellular signal-regulated kinase (ERK) pathway which is activated by neurotrophins and other neuroactive chemicals. The production of these chemicals effects neuronal differentiation, survival, regeneration, and structural and functional plasticity. Early studies of the ERK pathway showed that mood stabilizers for the treatment of manic-depressive illness stimulated this pathway. This led to the understanding that stimulation of the 5-HT2C receptors could also initiate less manic-depressive conditions like mood stabilizers do.
The 5-HT2C receptors are restricted to the CNS where they can be found in several locations, with the highest density in the choroid plexus (the bunch of capillaries that filter the blood to produce the cerebral spinal fluid). It can be found in other areas of the brain as well and typically those who are associated with regulation of food intake, including the nucleus of the solitary tract, dorsomedial hypothalamus, paraventricular hypothalamic nucleus and the amygdala. With the knowledge of their location, it might be possible to explain the effect they have in integral function in the control of many physiological and behavioral responses, such as feeding, anxiety, temperature regulation, locomotion, sexual behavior and the occurrence of seizures.
A Neurologic view
The state achieved when the need for food has been satisfied is called satiety. The satiety center in animals is located in the ventromedial nucleus of the hypothalamus. The destruction of this nucleus produces an overeating syndrome and obesity.
Short-term regulation of hunger and food intake involves neural signals from the GI tract, blood levels of nutrients, and GI tract hormones.
One method that the brain uses to evaluate the contents of the gut is through vagal nerve fibers that carry signals between the brain and the gastrointestinal tract (GI tract). Studies have shown that through these vagal nerve fibers, the brain can sense a difference between different macronutrients. Stretch receptors work to inhibit appetite upon distention of the GI tract by sending signals along the Vagus nerve afferent pathway and inhibiting the hunger center in the lateral nucleus of the hypothalamus (the destruction of this nucleus induces the animal to stop to eat).
Blood levels of glucose, amino acids, and fatty acids provide a constant flow of information to the brain that may be linked to regulating hunger and energy intake.
Nutrient signals that indicate fullness, and therefore inhibit hunger, include the following:
- Rising blood glucose levels;
- Elevated blood levels of amino acids;
- Blood concentrations of fatty acids.
The hormones insulin and cholecystokinin (CCK) are released from the GI tract during food absorption and act to suppress feeling of hunger. CCK is a key in suppressing hunger because of its role in inhibiting NPY (Neuropeptide Y). Glucagon and epinephrine levels rise during fasting and stimulate hunger. Ghrelin, a hormone produced by the stomach, is a powerful hunger stimulant.
Leptin, a hormone secreted exclusively by adipose cells in response to an increase in body fat mass, is an important component in the regulation of long term hunger and food intake. Leptin serves as the brain's indicator of the body's total energy stores. When leptin level rise in the bloodstream it binds to receptors in ARC (Arcuate Nucleus). The function of leptin is: to suppress the release of NPY, which in turn prevents the release of the appetite enhancing orexins from the lateral hypothalamus (center of Hunger). This decreases appetite and food intake, promoting weight loss.
Though rising blood levels of leptin does promote weight loss to some extent, its main role is to protect the body against weight loss in times of nutritional deprivation. Other factors also have been shown to effect long-term hunger and food intake regulation including insulin.
A right lifestyle
Today, the health is promulgated everywhere. We must find the right equilibrium for our body and our mind. Not always what is declared as healthy is true for our body (for instance, a new recipe); we must evaluate every single case that is offered to our attention.
When we try a new strategic diet, for example, for losing our weight, we must consider the temporal window in which the efficacy of the treatment (pills, diet, exercise, etc.) becomes evident. Other than this window, we must consider the maintenance of the result and the cost of it.
When we sit at the table during the meals time, we should ask ourselves: are we really starving or are we trying to relieve our stress through the pleasure of eating? Or are we just satisfying our gluttony? Is this just a conditioning?
We must ask ourselves the questions above. We could answer through other questions. How do I feel if I avoid eating? When should I eat? What should I eat? When should I stop eating? Do I need to fill my stomach or my mind?
We must carefully consider our needs on the base of our experience, age, life style and general health condition. Once we have done a deep analysis of our state, we can decide what to do and find the right answers to those questions.
The body caloric ratio, the BMR and BMI
Although there are differences of opinion over which ratios are most optimal for health and weight loss, many popular diets are based on a particular caloric ratio. For example, the USDA guidelines recommend that approximately 60% of the calories you consume should come from carbohydrates and approximately 30% from fat. Proponents of the Zone™ diet recommend a ratio (40%-30%-30%) much lower in carbohydrates but higher in protein. Advocates of the Atkins™ and South Beach™ diets recommend even lower consumption of carbohydrates, while many other diet philosophies focus on an ultralow consumption of fats.
Remember the rule of the energy conservation. Once you defined the purpose of your diet (losing weight, build muscles, etc.) you can establish a good caloric ratio. Try to preserve the amount of calories for each nutrient as much as you can. For example, if you are using a caloric ratio of 50:30:15 (%carbohydrates: %proteins: %lipids) you are taking approximately the same amount of calories for each nutrient.
Determine your personal basal metabolic rate or BMR. The BMR is your daily caloric needs needed for your body to perform its basic tasks, such as heart to beat, breathing, digesting, etc. This measurement can help you fine tune the calorie needs of your body with the Harris Benedict formula.
- The woman's American measurement BMR equation is: (4.7 x your height in inches) + (4.35 x your weight in pounds) - (4.7 x your age in years). Add 655 to this total for the BMR.
- The man's American measurement BMR equation is: (12.7 x your height in inches) + (6.23 x your weight in pounds) - (6.8 x your age in years). Add 66 to the total for the BMR.
Apply the Harris Benedict formula to calculate calories based on your activity level and BMR. All you have to do is multiply the BMR for your body by the number for your activity level.
- If you don't exercise or exercise little, multiply the BMR by 1.2 for daily calories.
- If you take part in light exercise or sports 1-to-3 days each week, multiply the BMR by 1.375 for daily calories needed.
- People who exercise moderately and/or play sports 3-to-5 days a week should multiply their BMR by 1.55
- Active people who engage in strenuous sports or hard exercise 6-to-7 days a week need to multiply their BMR by 1.725.
- People who engage in very physically challenging jobs or exercise, such as 2-a-day workouts, should multiply their BMR by 1.9 for daily caloric needs.
Obese people may overestimate daily calories with the Harris Benedict formula.
The BMR is different from the BMI (body mass index = Weight (lb) / (Height (in) x Height (in)) x 703). This last is a useful resource to determine the right weight for your physical constitution and the daily caloric need.
You must always pay attention even to few calories in the diet, because they have a cumulative effect over time on your weight.