Preamble on hunger vs. appetite and eating disorders
There seems to be a bit of ambiguity between the terms appetite and hunger so for the purpose of this guide we will treat appetite as the psychological desire to eat and the associated sensory cues elicited. Hunger is the physiological need for food (i.e. an organism requires nutrients to subsist).
While both appetite and hunger have their own designations, there is certainly interplay between them and one can influence the other. The hormones to be discussed in this guide are generally released in accordance with the body’s desire for nutrients (i.e. hunger) which subsequently influences one’s appetite.
My goal is to make this guide as educational and pragmatic as possible on a biochemical basis, so I don’t plan to talk much about the emotional attachment many people develop with food. Unfortunately the fitness and physique realms are now wrought with people who have developed disordered behaviors with their food intake and I am no psychologist or doctor so I won’t pretend to know the optimal way to treat those issues.
However, I will say that if you are at a point of unhealthy thinking towards food you need to address those issues head on before it gets out of hand. If you’re constantly brooding over your food intake, your appetite regulation is going to be skewed, so some of the following tips may preclude those with eating disorders. Maybe in a future article I will address the topic further just to stir the pot a bit and share my personal anecdote.
Is your appetite to blame?
With obesity more prevalent now then ever in our gluttony-encouraging society, it goes without saying that we need to take action to halt this epidemic in its tracks. The “American” lifestyle for many overweight individuals includes grossly exceeding their daily caloric needs due to mindless grazing on calorie-dense, nutrient-devoid foods while their primary exercise is the mighty voyage from the parking lot to their work desk.
So why is it exactly that people overeat (or under eat for that matter)? Well, there are a plethora of issues that contribute to over or under eating, but appetite regulation gone awry is definitely a major culprit. Various hormones secreted in the human body act as neuromodulators that influence cognitive behavior towards appetite (or lack thereof); we will be focusing on a few key hormones—ghrelin, leptin, and adiponectin.
After this overview of how appetite regulation works some suggestions will be provided on how to either increase or decrease your desire for that midnight pint of Ben & Jerry’s.
P/D1 cells in the stomach of humans and epsilon cells of the pancreas secrete ghrelin, a rather short peptide hormone of only 28 amino acids that induces orexigenic (appetite-stimulating) properties. (1) The receptors for binding gherlin are highly present throughout the vagus nerve in the gastrointestinal tract and also various brain components such as the hypothalamus and pituitary gland. (2)
These receptors are growth hormone secretagogue receptors which, when bound with gherlin, upregulate secretion of growth hormone from the pituitary gland. (3) In fact, this is one of the reasons growth hormone is used as a performance enhancing ancillary (e.g. it increases appetite for those looking to build as much muscle as possible).
The “eat slow” tip
The mechanism of action for gherlin involves stimulation of neuropeptide Y (NPY) neurons in the acruate nucleus region of the hypothalamus (growth hormone acts in a similar manner to stimulate appetite). (4) Subsequently, expression of NPY stimulates the mesolimbic reward center that is responsible for the pleasurable feelings during eating and other activities (mostly due to the increase of dopamine and serotonin in the brain).
Shortly after the initiation of eating, anorexigenic peptides, such as leptin, glucagon-like peptide 1, and cholecystokinin secrete satiety signals. (5) This is why it is often advised to eat slow as this allows your brain the necessary time to antagonize the orexigenic pathway by secreting anorexigenic peptides that induce satiety. Of course, you’d want to do the inverse if you’re trying to scarf down that entire king-size double Whopper meal in record time. Hopefully that wasn’t too terribly scientific for the readers; it’s a downhill slide from here so stick with me!
The leptin breakthrough—hormones from fat cells?
Prior to the discovery of leptin, it was unknown that fat cells were much more than dormant “insulators” to pad that nice round booty of yours. Well, it is now know that fat cells are indeed alive like any other cell in your body and they secrete hormones called adipokines.
Leptin, an adipokine secreted mostly in white adipose tissue, derives many pronounced effects from neuromodulation of peptides in the hypothalamic-pituitary-thyroid axis (HPTA).6 Leptin has major implications on hunger signaling and is antagonistic to ghrelin; ghrelin works to stimulate orexigenic neuropeptides while leptin is supposed to stimulate anirexogenic (appetite-decreasing) neuropeptides. Hence, leptin’s primary roles are regulating metabolic expenditure as well as caloric intake, both of which have obvious implications with regards to bodyweight.
The conundrum with leptin is that is positively correlated with body fatness, but in the case of obesity studies have shown there appears to be a down-regulation of leptin receptor activity in overweight individuals; this would explain why overweight people continue to consume excessive amounts of food despite having high levels of circulating leptin. (7) So the issue with leptin isn’t necessarily concern over having high or low blood values, but optimizing receptor activity (it is analogous to insulin resistance in type-2 diabetics).
Furthermore, a study in 1998 published by the Journal of Biological Chemistry found that exogenous doses of leptin in rats increased insulin sensitivity, as well as improved glucose regulation via hepatic suppression of gluconeogenesis. (8) Granted these rats were relatively lean, this could still be a sign of a positive outlook on leptin drug development to use in tandem with current diabetic regimens for treatment of the insulin resistance that often occurs in obese individuals.
The second adipokine to be discussed is adiponectin. Adiponectin, also a protein hormone secreted by adipose tissue, is thought to be complementary to leptin in its mechanism of action. Adiponectin’s primary endogenous activity appears to be in the oxidation of fatty acids and downregulation of hepatic glucose production. (9) There is a negative correlation between body fatness and adiponectin levels (high body fat=lower adiponectin levels).
Possible implications of chronically depressed adiponectin levels include the onset of atherosclerosis and type-2 diabetes (insulin resistance). Exogenous administration of thiazolidinediones have been shown to reverse insulin resistance in accordance with the elevation of adiponectin levels. (9) In contrast, pro-inflammatory cytokines, such as TNF-alpha oppose the actions of thiazolidinediones and inhibit adiponectin.
Reality check time—there is no miracle drug…yet
The ramifications of leptin resistance and low adiponectin levels should be quite clear by now, and if they aren’t then I have clearly failed you. The correlation of these conditions to obesity is no coincidence either. While the most obvious route of reversal for obese individuals is proper diet and exercise, it is intriguing to see what pharmaceutical and supplemental interventions are in the works to augment leptin receptors and increase adiponectin levels.
Along with the development of the aforementioned thiazolidinediones and leptin analogs, drug treatment and prevention of obesity could benefit largely from antagonism of the gherlin peptide or modification of gherlin receptors. Currently in development are antibiotic drugs that bind gherlin peptides seeking to inhibit gherlin’s action by directing the body’s immune system against the peptide. (10)
It would seem efficient in the case of overweight individuals to reduce the hunger signaling brought on by gherlin reaching the central nervous system. Certain contradictions could occur however, such as eating too little and subsequently being deficient in micronutrient intake. While it is good for obese individuals to restrict their caloric intake to a level that is suitable for consistent weight loss, they still need to eat; starving them is not the goal.
At the end of the day, the not-so-harsh reality is you’re going to have to get up and move and eat properly if you really want to avoid the consequences of being overweight. But fear not, there are still certain aides to assist you in your goals which we will look at below.
Tips to master your appetite and control food intake
For now, we stick to the “au naturel” route and see what can be done to influence appetite without a prescribed drug.
“Either-or” appetite regulating tips (*may increase or decrease your appetite):
A few big meals versus many small meals
I don’t want this to be yet another debate on meal frequency and timing so frankly I won’t advocate for either the “bro” diet of 6-7 smaller meals versus someone who eats 1-3 bigger meals per day; just do whatever suits your lifestyle. My take is that your hunger signaling and appetite are trainable, so some people have no issue going many hours without food if they’ve adapted to that sort of eating pattern.
This is tough to categorize as the hormonal responses to various exercise intensities can work to stimulate appetite or decrease it. While exercise is absolutely beneficial, it will take some trial and error to see how it influences your appetite. Regardless, if you’re looking to eat more or less, don’t neglect exercise.
I’m sure many people are aware of “stress eating” which seems to be a common occurrence in depressed individuals. On the same token, some people may deal with stress and anxiety by avoiding food. It can only be of benefit for you to manage your stress/anxiety so you encourage a calm, pleasant mood which will usually positively affect your appetite regulation.
Get adequate sleep
Even acute losses of sleep have been shown to have a host of deleterious effects in humans, including the tendency to overeat the next day and concomitant decreases in insulin sensitivity, two things that spell disaster when combined.16 Sleep loss usually results in feeling stressed out as well, which as aforementioned is generally not favorable for good appetite regulation.
Decreasing your appetite/food intake (sans supplements):
This is a pretty elementary tip because it’s based on basic physiology; as mentioned earlier in this article, eating slowly gives your brain and gut time to connect and recognize you’re filling up.
Eat foods that provide more satiety early in your meals/day:
Fibrous vegetables/fruits are micronutrient-dense, lower-calorie options that provide bulk to waste in the intestines, hence you feel fuller.
Hi-water content foods such as soups, low-fat dairy, beans, lean meats, poultry, fish, fruits, veggies and certain cooked grains are generally lower in calorie density. Essentially, you get more “bang for your buck” with these options because the water promotes fullness and adds volume to your food.
Drink ample amounts of water (or other low-calorie liquids)
The benefits of staying hydrated are rather numerous, and keeping enough liquid in your stomach while you eat can create a sense of fullness (not to mention it’s good for digestive purposes).
Get your mind off of food
Seems pretty intuitive, but when you sense a hunger pang coming on the last thing you want to do is be around the kitchen when mama is whipping up her famous banana cream pie. Try and keep yourself preoccupied with other things and you’ll notice you stop worrying about food so much.
Plan/prep your meals ahead of time
For many individuals just having an established plan ahead of time will prevent you from walking around the kitchen and grazing until you feel satisfied. I’m in favor of writing out what your goal macronutrient breakdown is and then just filling in the numbers with the necessary amounts of foods that you’re in the mood for.
Supplemental appetite suppressants (list is not exhaustive, just the more popular ingredients):
A trace biological mineral that is purported to improve carbohydrate metabolism and increase serotonin levels as well as decrease serum cortisol levels, which are all positives when seeking appetite suppression. (11) I recommend the polynicotinate form as it is more bioavailable.
Intermediate metabolite between L-tryptophan and serotonin. Generally extracted from the plant Griffonia simplicifoli. The theory here is that serotonin eases stress and thus appetite will be reduced since many people “stress eat”. (12)
These are all stimulant based compounds that should only be used in moderation; for appetite-suppressing purposes I generally advocate non-stimulants around meal times and save these for times around your workout.
A soluble and highly viscous dietary fiber derived from the root of the elephant yam or konjac plant. Studies have shown significant benefits in promoting satiety and improved lipid profiles. (13)
A bit more underwhelming than the other compounds listed here as the studies have haven’t really proven hoodia’s efficacy in nominal doses. (14) If you can find it cheap then it may be worth a try.
White Kidney Bean Extract
A relatively new compound in the supplement world that is purported to have anorexigenic activity via inhibition of alpha-amylase. (15)
*The doses necessary for appetite suppression will vary for many individuals so please follow the label instructions when starting any of these supplements.*
Increasing your appetite/food intake (sans supplements):
Seems obvious, but do the inverse of the above tips for decreasing appetite—Why do you think Kobayashi and Joey Chestnut are so successful at dominating the annual Nathan’s hot dog eating contest? They eat fast, they limit water intake during the feeding, and hot dogs are low-fiber and calorie-dense. Obviously this is an extreme example, but the point is that if you’re the type that struggles to eat enough calories for supporting your goals, then you want to emphasize foods that won’t fill you up too quick so you are able to reach your nutrient needs.
Add lime juice to your water
This is a neat trick that works by acidifying your water which will subsequently stimulate your gastric production of hydrochloric acid (an important enzyme that helps breakdown food)
Sip, don’t chug liquids while eating
Try to limit liquid intake during your meals as they can fill you up. Studies have gone back and forth on whether drinking liquids before, during or after meals is most optimal for digestion but anecdotally you will likely find that saving most of your drink for after the meal will help with digestion.
Eat cold/room temperature foods
The theory behind this is that warm/hot foods have stronger odors and may be harder to eat a lot of for those averse to said smells. Also, hot food generally takes longer to eat which will likely inhibit your ability to eat a whole lot.
Use bigger dishware
Sort of a quirky trick on your own perception, but using larger dishes may help you eat more without really knowing it.
Supplemental appetite enhancers:
Vitamin B9 (folic acid)
This is actually one of the few supplements that has been shown in clinical research to stimulate appetite. (17) It appears to increase digestive acids which promotes appetite increase.
Vitamin B12 (cobalamin)
Studies have gone back and forth on vitamin B12 and whether it increases appetite. It is however good for synergistic use along with folic acid, so this would be favorable to include if you decide to try that. (18) B12 is best taken as an injection (requires a prescription) or sublingually.
Iron-deficiency anemia is correlated with decreased appetite and restoration of normal iron levels has been shown to improve appetite. (19)
Often times a lack of appetite can be due to poor digestion/absorption of nutrients. Using a complex of digestive enzymes may improve the condition. Consider enzymes such as pepsin, betaine HCL, lactase and alpha amylase.
Similar in theory to the use of digestive enzymes, probiotics promote healthy gut flora which assist in keeping digestion up to par.
Various plants are used in many cultures to naturally treat poor appetite. These can include things such as gentian, peppermint leaves, ginger root, licorice root, bitter orange, ginseng, and fennel seed. (20)
Hey dude, what about marijuana?
As of the time that I am composing this guide marijuana isn’t legally sold OTC (in the USA) so I can’t recommend you to go find the nearest disciple of the Marley bandwagon and chief the reef.
*Your mileage may vary with some of these, but if you really need help increasing appetite they’re generally inexpensive and worth a shot.
Bringing it all together
I hope this guide has taught you a fair bit about how the body regulates appetite/hunger signals and you can use this knowledge to positively influence your nutritional habits. As always, try optimizing your behaviors/lifestyle before plunking down your hard-earned money on supplements. I would also advise to try adding supplements one at a time so you can figure out which of them actually helps. Most importantly, always discuss supplement use with your physician prior to initiation.
1. Inui A, Asakawa A, Bowers CY, et al. (2004). "Ghrelin, appetite, and gastric motility: the emerging role of the stomach as an endocrine organ". FASEB J. 18 (3): 439–56.
2. Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K (1999). "Ghrelin is a growth-hormone-releasing acylated peptide from stomach". Nature 402 (6762): 656–60.
3. Castañeda TR, Tong J, Datta R, Culler M, Tschöp MH (2010). "Ghrelin in the regulation of body weight and metabolism". Front Neuroendocrinol. 31 (1): 44–60.
4. Hewson AK, Dickson SL (2000). "Systemic administration of ghrelin induces Fos and Egr-1 proteins in the hypothalamic arcuate nucleus of fasted and fed rats". J Neuroendocrinol. 12 (11): 1047–1049.
5. Journal of Pediatric Gastroenterology & Nutrition: December 2010 - Volume 51 - Issue - p S123–S124
6. Hebebrand, J, Td Muller, K Holtkamp, and B Herpertz-Dahlmann. "The role of leptin in anorexia nervosa: clinical implications." Molecular Psychiatry aop.current (2003): 1409-1421. Print.
7. Jéquier E. Leptin signaling, adiposity, and energy balance. Ann N Y Acad Sci. 2002 Jun; 967:379-88. Review. PubMed PMID: 12079865. Cited in PMCRelated citations
8. Liu L, Karkanias GB, Morales JC, Hawkins M, Barzilai N, Wang J, Rossetti L. Intracerebroventricular leptin regulates hepatic but not peripheral glucose fluxes. J Biol Chem. 1998 Nov 20;273(47):31160-7. PubMed PMID: 9813020.
9. Lihn AS, Pedersen SB, Richelsen B. Adiponectin: action, regulation and association to insulin sensitivity. Obes Rev. 2005 Feb;6(1):13-21. Review. PubMed PMID: 15655035.
10. Vizcarra JA, Kirby JD, Kim SK, Galyean ML (August 2007). "Active immunization against ghrelin decreases weight gain and alters plasma concentrations of growth hormone in growing pigs". Domest Anim Endocrinol. 33 (2): 176–89.
11. Komorowski JR, Tuzcu M, Sahin N, Juturu V, Orhan C, Ulas M, Sahin K. Chromium picolinate modulates serotonergic properties and carbohydrate metabolism in a rat model of diabetes. Biol Trace Elem Res. 2012 Oct;149(1):50-6. doi: 10.1007/s12011-012-9393-x. Epub 2012 Mar 22. PubMed PMID: 22434381.
12. Halford JC, Harrold JA, Lawton CL, Blundell JE. Serotonin (5-HT) drugs: effects on appetite expression and use for the treatment of obesity. Curr Drug Targets. 2005 Mar;6(2):201-13. Review. PubMed PMID: 15777190.
13. Keithley J, Swanson B. Glucomannan and obesity: a critical review. Altern Ther Health Med. 2005 Nov-Dec;11(6):30-4. Review. PubMed PMID: 16320857.
14. Whelan AM, Jurgens TM, Szeto V. Case report. Efficacy of Hoodia for weight loss: is there evidence to support the efficacy claims? J Clin Pharm Ther. 2010 Oct;35(5):609-12. doi: 10.1111/j.1365-2710.2009.01116.x. PubMed PMID: 20831685.
15. Hypoglycaemic and anorexigenic activities of an a-amylase inhibitor from white kidney beans (Phaseolus vulgaris) in Wistar rats, British Journal of Nutrition (2004), 92, 785–790.
16. Benedict C, Brooks SJ, O'Daly OG, Almèn MS, Morell A, Åberg K, Gingnell M, Schultes B, Hallschmid M, Broman JE, Larsson EM, Schiöth HB. Acute sleep deprivation enhances the brain's response to hedonic food stimuli: an fMRI study. J Clin Endocrinol Metab. 2012 Mar;97(3):E443-7. doi: 10.1210/jc.2011-2759. Epub 2012 Jan 18. PubMed PMID: 22259064.
17. "Vitamin B9 benefits: MedlinePlus Medical Encyclopedia Image." National Library of Medicine - National Institutes of Health. N.p., n.d. Web. 24 Feb. 2013. <http://www.nlm.nih.gov/medlineplus/enc>.
18. "Vitamin B Complex." American Cancer Society | Information and Resources for Cancer: Breast, Colon, Lung, Prostate, Skin. N.p., n.d. Web. 24 Feb. 2013. <http://www.cancer.org>.
19. Rebecca J. Stoltzfus, et al. “Low Dose Daily Iron Supplementation Improves Iron Status and Appetite but Not Anemia, whereas Quarterly Anthelminthic Treatment Improves Growth, Appetite and Anemia in Zanzibari Preschool Children” J. Nutr. 2004 134: 2 348-356
20. "Medical Herbalism: The Science and Practice of Herbal Medicine"; David Hoffmann; 2003
I have to say, it is wonderful to read a meaningful article about health. I read so many articles out there these days that tell me what to do to obtain a goal, whether it would be weight loss or building muscle. Rarely do I have the pleasure of reading an article that explains the science behind what I am doing. It is refreshing and puts subsequent meaning into obtaining a healthy lifestyle.