Leptin is a hormone produced by our fat cells that regulates how much we eat and the amount of energy we burn. Its main function is to signal the brain when we have eaten enough and are satiated, thus promoting weight loss. However, sometimes the body becomes resistant to the effects of leptin, and this can lead to overeating and weight gain. This condition is known as leptin resistance.
Leptin resistance occurs when the body stops responding to the signal produced by the hormone. This can happen due to a number of reasons, but the most common is excess body fat. Excessive amounts of fat in the body lead to a constant release of leptin, and over time the brain becomes desensitized to the signal. When this happens, the body thinks it’s starving and sends signals to increase appetite and store more fat, leading to weight gain.
There are other factors that contribute to the development of leptin resistance such as poor diet, lack of exercise, poor sleep, and high-stress levels. A diet high in sugar, processed foods, and saturated fats has been shown to increase inflammation levels in the body, which can affect how leptin is produced and how it functions.
Another factor that contributes to leptin resistance is lack of sleep. Poor sleep can affect the production of leptin, making it difficult for the body to regulate food intake and energy expenditure properly.
The good news is that leptin resistance is reversible. By maintaining a healthy diet and exercise routine, and reducing stress levels, you can gradually reduce the amount of fat in your body and restore proper leptin function. Studies have shown that consuming a high-fiber, low-fat diet can help reduce inflammation levels and promote weight loss, therefore improving leptin sensitivity.
Other interventions that can improve the body’s response to leptin include getting enough sleep, reducing stress levels through yoga or meditation practices, and starting a regular exercise routine. Resistance training, in particular, has been shown to be effective in improving the function of leptin.
In conclusion, leptin resistance is a condition that contributes significantly to overweight and obesity, and its prevalence continues to increase worldwide. Therefore, it is important to understand its causes and how to mitigate them. Maintaining a healthy diet, getting enough sleep, exercising regularly, and managing stress levels are ways by which you can address leptin resistance and achieve your weight loss goals.
References:
Rosenbaum M, Leibel RL. Role of energy expenditure in the development of leptin resistance. J Clin Invest. 2014;124(2): 420-2.
Juge-Aubry CE, Henrichot E, Meier CA. Adipose tissue: a regulator of inflammation. Best Pract Res Clin Endocrinol Metab. 2005;19(4):547-566.
Halpern B, Mancini MC. Leptin reduction and its interactions with diabetes control after bilio-pancreatic diversion. Surg Obes Relat Dis. 2009;5(1):48-53.
Lopez-Jaramillo P, Gomez-Arbelaez D, Lopez-Lopez J, Lombana-Rodriguez HA, Paez-Canro C, Rueda-Quijano SM, et al. The role of leptin/adiponectin ratio in metabolic syndrome and diabetes. Horm Mol Biol Clin Investig.[Internet] 2014;19(3):167-176. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25403381
Consitt LA, Saxena G. Exercise training and insulin resistance: a current review. J Obes.[Internet] 2013;2013: Vaiycn858690. Available from: https://www.ncbi.nlm.nih.gov/pubmed/23533342
The scientific community is still in disagreement as to whether or not obesity is a disease. While some still consider obesity a self-inflicted disease caused by poor eating habits and lack of exercise, there is growing evidence to support the claim that obesity is a disease.
According to Pi-Sunyer (2002), not only is obesity a disease but within the United States it is considered to be a condition of epidemic proportions. Statistics show that, in our country, over 20% of adults are diagnosed as clinically obese (Pi-Sunyer, 2002). The rationale that obesity is a disease is due to the fact that it causes many different comorbidities such as high blood pressure, diabetes, heart disease, etc.
Has Obseity Reached Epidemic Proportions In Western Countries?
I agree with Conway and Rene (2004) who believe that obesity is not only a condition that has reached epidemic proportions, but it is a disabling, multifaceted disease that causes changes in organ function and can come with a host of comorbidities. The excess body weight puts a strain on the heart, leading to changes in anatomical structure and the function of the organ. Obesity has also repercussions on the immune system (de Heredia et al., 2012), endocrine system (Poddar et al., 2017), and pulmonary system (Dixon & Peters, 2018). These repercussions are caused by both mechanical and functional alteration of tissues and organs.
Data Suggests That Obseity Is Associated With Several Very Serious Health Concerns
Research studies show that obesity is associated with an increased risk of developing cancer in at least 13 different organs (Avgerinos et al., 2019). Obesity is also linked to type-2 diabetes (Maggio & Pi-Sunyer, 2003), arthritis (Moroni et al., 2020). At the same time, a systematic review of scientific data that was published in 2017 shows that weight-loss interventions in the obese adult population decrease all-cause mortality (Ma et al., 2017). The same review shows that weight loss has a positive impact on cardiovascular mortality and cancer mortality (Ma et al., 2017).
Lastly, obesity’s status and acceptance as a disease are pivotal in determining its treatment, reimbursement for treatment, and the development of widespread interventions. For these reasons, I believe that obesity should be recognized as a disease.
References
Avgerinos, K. I., Spyrou, N., Mantzoros, C. S., & Dalamaga, M. (2019). Obesity and cancer risk: Emerging biological mechanisms and perspectives. Metabolism: clinical and experimental, 92, 121–135. https://doi.org/10.1016/j.metabol.2018.11.001
de Heredia, F. P., Gómez-Martínez, S., & Marcos, A. (2012). Obesity, inflammation and the immune system. The Proceedings of the Nutrition Society, 71(2), 332–338. https://doi.org/10.1017/S0029665112000092
Ma, C., Avenell, A., Bolland, M., Hudson, J., Stewart, F., Robertson, C., Sharma, P., Fraser, C., & MacLennan, G. (2017). Effects of weight loss interventions for adults who are obese on mortality, cardiovascular disease, and cancer: systematic review and meta-analysis. BMJ (Clinical research ed.), 359, j4849. https://doi.org/10.1136/bmj.j4849
Maggio, C. A., & Pi-Sunyer, F. X. (2003). Obesity and type 2 diabetes. Endocrinology and metabolism clinics of North America, 32(4), 805–viii. https://doi.org/10.1016/s0889-8529(03)00071-9
Moroni, L., Farina, N., & Dagna, L. (2020). Obesity and its role in the management of rheumatoid and psoriatic arthritis. Clinical rheumatology, 39(4), 1039–1047. https://doi.org/10.1007/s10067-020-04963-2
Pi-Sunyer, F. X. (2002). The obesity epidemic: Pathophysiology and consequences of obesity. Obesity Research, 10(S12), 97S-104S. https://doi.org/10.1038/oby.2002.202
Poddar, M., Chetty, Y., & Chetty, V. T. (2017). How does obesity affect the endocrine system? A narrative review. Clinical obesity, 7(3), 136–144. https://doi.org/10.1111/cob.12184
Our total daily energy expenditure (TDEE) is dictated by three factors: resting metabolic rate (RMR), which is the number of calories our body needs to perform metabolic functions when it is at rest; the number of calories burnt through physical activity, non-exercise activity thermogenesis (NEAT), and exercise; and the number of calories needed to digest and absorb food. This is called diet-induced thermogenesis (DIT) or thermal effect of feeding (TEF).
Total daily energy expenditure varies from individual to individual and across age, sex, total body weight, physical activity, percentage of fat free mass (FFM), also called lean body mass, versus fat mass (FM), as well as hormones; all play a role in TDEE. In general, RMR accounts for 60% of TDEE, physical activity account for 25-35% of TDEE, and DIT accounts for 5-15% of total energy expenditure.
How Is Food Converted Into Usable Energy?
The foods and beverages that we consume are combined with oxygen and converted into energy in the form of ATP. They also provide the building blocks used to make hormones and enzymes to grow and repair tissue as well as many other processes. When we eat, digest and assimilate food we burn calories. Diet-induced thermogenesis begins immediately after we eat and can last several hours, depending on the macronutrient composition of the meal. The word thermogenesis comes from the Greek θερμός (thermos) and γένεση (genesis), and it means the creation of heat. Not only does DIT create heat during food digestion and absorption, but it also (by a mechanism still not completely understood) activates the sympathetic nervous system which causes the body to produce heat in brown adipose tissue (BAT). BAT is only stimulated by cold temperatures (shivering) and food consumption.
What Exactly Is A Calorie?
A calorie is a unit of energy. It would be simple to think that a calorie is a calorie and that, therefore, 100 calories of steak are the same as 100 calories of brownies, or butter, or broccoli. But different macronutrients require different amounts of ATP to be metabolized and stored. This is why different macronutrients have different thermogenic effects, and DIT can vary greatly depending on the macronutrient composition of our diet.
Protein and alcohol have the highest thermic effects. The DIT for protein is calculated to be between 20 to 30%; the DIT of alcohol is between 10 and 30%. The thermic effect of carbohydrates is between 5 and 10%, and fat has the lowest reported DIT: 0 to 3%. This means that given the same number of calories, meals rich in protein, fat, carbohydrate, or alcohol have different effect on energy expenditure.
Studies show that postprandial thermogenesis in healthy subjects is increased 100% on a high-protein/low-fat diet versus a high-carbohydrate/low-fat carbohydrate diet. In addition, compared to fats and carbohydrates, protein consumption also provides increased satiety. Satiety scores were higher during high protein/high carbohydrate meals versus high fat meals. For these reasons, high protein diets are favored for weight loss as well as for weight maintenance.
How Does Food Effect Metabolism?
When researching the effects of food on metabolism, the next logical question to address is the following: would eating many smaller meals burn more calories than eating one to two larger meals in a 24-hour period? I found contradicting studies when reviewing the literature. Some studies showed that nibbling throughout the day caused a greater caloric expenditure, while other studies showed that consuming larger meals was linked to greater caloric expenditure. It seems that when it comes to meal frequency and metabolism the jury is still out.
There are other nutrients that stimulate metabolism and cause thermogenesis without contributing any calories. These nutrients are caffeine, capsaicin, and cold water. Caffeine is an alkaloid found in coffee beans, tea leaves, and cocoa beans. It is a stimulant and studies show that a cup of coffee can boost metabolism by 3-11%. A study also showed that caffeine may affect lean people more than overweight people as fat burning in lean women increased by 29% with caffeine consumption but obese women registered an increase of only 10%. Capsaicin is a compound found in chili peppers that stimulates metabolism and helps reduce energy intake. Finally, consuming water increases metabolism by 10-30% for about an hour. Cold water may promote an even greater caloric expenditure, as the body uses extra energy to raise the water temperature to body temperature.
References:
Raben A, Agerholm-Larsen L, Flint A, Holst JJ, Astrup A. Meals with similar energy densities but rich in protein, fat, carbohydrate, or alcohol have different effects on energy expenditure and substrate metabolism but not on appetite and energy intake. Am J Clin Nutr. 2003 Jan;77(1):91–100.
Westerterp-Plantenga MS, Rolland V, Wilson SA, Westerterp KR. Satiety related to 24 h diet-induced thermogenesis during high protein/carbohydrate vs high fat diets measured in a respiration chamber. Eur J Clin Nutr. 1999 Jun;53(6):495–502.
Acheson KJ: Influence of autonomic nervous system on nutrient-induced thermogenesis in humans. Nutrition. 1993, 9 (4): 373-80.
Hermsdorff HHM, Volp ACP, Bressan J. [Macronutrient profile affects diet-induced thermogenesis and energy intake]. Arch Latinoam Nutr. 2007 Mar;57(1):33–42.
Jequier E. Thermogenic responses induced by nutrients in man: their importance in energy balance regulation. Experientia Suppl. 1983;44:26–44.
Scott CB, Devore R. Diet-induced thermogenesis: variations among three isocaloric meal-replacement shakes. Nutrition. 2005 Jul 1;21(7):874–7.
The ideal body weight, IBW, is the optimal weight based on gender and height. The ideal weight for a woman my height, 5’ 3”, is 104 to 140 pounds. Unfortunately, ideal body weight is an incomplete measurement and does not necessarily reflect the health of a person. Height and gender are the primary factors determining ideal body weight, and some calculators take age into consideration. However, build, muscular development, and body fat percentage are not taken into account. Because of this, many athletes and fit individuals may be considered overweight based on the ideal body weight, while so-called skinny fat people may be well within their ideal body weight numbers.
The Ideal Healthy Body Has Little To Do With The Pounds Displayed On The Scale
When working with clients, I encourage them to ditch the scale and measurements like IBW and to focus instead on body composition, inches lost instead of pounds lost, and, if they really want to explore body composition and have some money to spend, I recommend utilizing tools like Dexa body composition scan and whole body phethysmography.
Excess body weight and body fat have a negative impact on health, and they come with numerous health risks, from type 2 diabetes to sleep apnea. One of the systems that is negatively impacted by obesity and being overweight is the cardiovascular system. Excess body fat is a major contributor to hypertension, which is the number-one cause of stroke. It is also harmful to the kidneys. People who are overweight or obese are also at higher risk for chronic inflammation and diseases of infertility like polycystic ovarian syndrome.
Being overweight or obese is also linked to at least 13 different types of cancers (including breast, thyroid, uterus and ovaries, as well as colon and rectum cancer). While the exact mechanisms aren’t clear, some possible ways in which excess body fat contributes to cancer concern DNA damage resulting from chronic inflammation. The estrogenic effect of fat tissue most likely increases risk of endometrial, breast, ovarian and uterine cancer. Obesity is also linked to high blood levels of insulin and IGF-1, which promote tumor development by inhibiting programmed cell death. Fat cells also produce the hormones adipokines, which have the ability to stimulate or hinder cell growth. It goes without saying that maintaining a healthy body weight is foundational for cancer prevention.
The Mediterranean Diet And Healthy Body Size
The Mediterranean diet is touted as one of the healthiest of the planet. There is not one Mediterranean diet but several variations, depend on the region. While different Mediterranean countries eat different foods, there are staples consumed throughout the Mediterranean, from Italy to Greece to Spain: fresh seasonal vegetables, fish, lamb, nuts, legumes, herbs and spices, some nuts and seeds, and our stars: olives and olive oil. The Mediterranean diets avoid added sugars, highly processed foods, trans-fats, and refined vegetable oils. Water is the beverage of choice; coffee and teas are widely consumed, and wine is also included in moderation.
The Mediterranean diet is rich in fiber and healthy fats, and it is the diet of choice for heart health. Studies show that it improves lipid profiles, decreases lipid oxidation and reduces risk of thrombosis.
The Paleolithic Diet And Reaching Ideal Body Composition
The Paleolithic diet focuses on the foods eaten by our ancestors during the Paleolithic era, when humans were hunter-gatherers. While there are several variants of the diet, the Paleolithic diet (or “paleo”) removes sugar, processed foods, vegetable oils, trans-fats, legumes and grains. It includes meat, poultry, fish, vegetables and fruit, nuts and seeds. Some variations incorporate dairy. Potatoes were initially excluded, but in recent years they have been added to the list of allowed foods. The paleo diet therefore removes many inflammatory foods (processed foods, trans-fats), as well as foods that trigger food sensitivities (gluten and dairy). A 2009 study showed that the Paleolithic diet was superior to the diabetes diet in managing cardiovascular risk factor in patients with type 2 diabetes. Other studies show improvement in serum biomarkers for cardiovascular disease.
Paleolithic Diet Versus Mediterranean Diet
While both diets are beneficial for cardiovascular disease, my preference would be to start a client on the Paleo diet. I like using the paleo diet as an elimination diet. Usually, after an initial phase (lasting 1 to 2 months depending on the client), I carefully and slowly reintroduce foods allowed in the Mediterranean diet. This allows added variety which can help stave off boredom which is extremely important for compliance. Ultimately, the choice will be the client’s. It would be unwise to recommend a Paleo diet to a client who is not likely to comply with such restrictive way of eating. In my practice, clients are active participants in setting goals and how to reach them.
References:
Ortega‐Loubon, C., Fernández‐Molina, M., Singh, G., & Correa, R. (2019). Obesity and its cardiovascular effects. Diabetes/metabolism research and reviews, 35(4), e3135.
Peterson, C. M., Thomas, D. M., Blackburn, G. L., & Heymsfield, S. B. (2016). The universal equation for estimating ideal body weight and body weight at any BMI. The American journal of clinical nutrition, 103(5), 1197-1203.
Obesity and Cancer Fact Sheet – National Cancer Institute [Internet]. 2017 [cited 2020 Nov 2]. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/obesity/obesity-fact-sheet
Dağ ZÖ, Dilbaz B. Impact of obesity on infertility in women. J Turk Ger Gynecol Assoc. 2015;16(2):111–7.
Virani, S. S., Alonso, A., Benjamin, E. J., Bittencourt, M. S., Callaway, C. W., Carson, A. P., … & Djousse, L. (2020). Heart disease and stroke statistics—2020 update: a report from the American Heart Association. Circulation, E139-E596.
Mediterranean diet for heart health [Internet]. Mayo Clinic. [cited 2020 Nov 2]. Available from: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801
Jönsson T, Granfeldt Y, Ahrén B, Branell U-C, Pålsson G, Hansson A, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009 Jul 16;8:35.
Sharman MJ, Kraemer WJ, Love DM, Avery NG, Gómez AL, Scheett TP, et al. A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. J Nutr. 2002 Jul;132(7):1879–85.
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