Millions of people go on diets every year, but by the end of the year, most of them have regained any weight lost and find themselves starting back at square one. After all, dieting is no easy feat, and it might even be harder than you think! Your body has an appetite, and if you consistently take in fewer calories than you burn, your body responds by revving up your appetite hormones, making you hungrier.
It's not uncommon to hear names like insulin, testosterone, estrogen, and cortisol thrown around when talking about hormones that affect body fat. For example, insulin is often cited as a fat-storage hormone and criticized for being a key contributor to weight gain and obesity. While this is oversimplified and not entirely true, there are two hormones that may play a much larger and more direct role in weight gain and weight management: leptin and ghrelin.
These two hunger hormones can directly affect energy balance and play a much bigger role in weight-loss success.1 If you want to improve your body composition and be successful with long-term weight management, understanding the role of these two hormones and how you can manipulate them is key!
What Is Leptin?
Leptin is considered the master regulator of hunger, and is known as your appetite suppressor. Leptin influences food intake due to its effect on the hypothalamus, a region of the brain that governs many processes and emotions such as hunger, thirst, sleep, and mood.
For example, when you eat a meal, leptin levels increase. This sends a signal to the brain telling your body that it's full and to put the fork down. However, if an individual is leptin-resistant, or if the leptin pathway isn't working properly, they may continue to overeat and often have poor control over food intake—in other words, they overeat without even knowing it.2
For these reasons, it's easy to understand why leptin plays a key role in long-term dietary adherence and success.
The Leptin Spiral
Leptin is stored in and secreted by fat cells. As you gain more fat mass, leptin levels increase to tell your brain to eat less and burn more calories. Conversely, if you cut down your calories and start to lose body fat, leptin levels go down, which then sends a signal to your brain to eat more and burn less! Think of this conundrum as a safety mechanism that regulates energy expenditure and food intake.3
Based on this information, you would think someone carrying around extra body fat would have more leptin, and thus, fewer desires to overindulge in food. This sounds great in theory, but research has shown that despite an elevation in leptin levels, obese individuals continue to overeat and energy expenditure fails to increase significantly.
This is called leptin-resistance. As someone gains weight, the signal to their brain can get "disrupted" or become less "sensitive," which causes them to continually overeat.4
Lifeline Your Leptin Levels
If your goal is weight loss or maintenance, leptin resistance is obviously an important issue. In fact, it's currently considered one of the largest biological causes of obesity.5 Losing body fat is one obvious way to fix leptin resistance, but it takes more than a flash-in-the-pan diet. To really make a difference and correct leptin resistance long term, consider these strategies:
Swap out Junk Food for Fruits and Veggies
Excessive inflammation may disturb the signaling mechanism of leptin on the hypothalamus. Eating a primarily unprocessed diet high in fruits and vegetables—along with certain supplements such as omega-3 and antioxidants—may help reduce inflammation.6
While cookies and snack cakes may taste good, they are typically less satiating than whole foods, they're extremely calorie dense, and they provide little nutrition to your diet.
Break a Sweat
Regular exercise plays an important part in improving leptin resistance and decreasing inflammation.6 Make sure to include resistance and high-intensity interval training, which will not only help control leptin levels, but are great for building muscle and burning fat.
If you need a complete workout regimen, check out Find a Plan, which has complete training, nutrition, and supplement programs for your specific needs.
Increase Protein Intake
Along with helping you feel fuller longer, protein may also improve leptin sensitivity.7 Aim for 30 grams of lean protein per meal. This can include chicken breast, white fish, tofu, or lean ground beef.
Get More Sleep
Alongside the abundant benefits of a good night's sleep, logging eight hours of shut-eye on a regular basis may also help improve leptin sensitivity.8 If you struggle with falling asleep, try some of these tips: Set a regular bedtime, turn off your TV or computer thirty minutes before you hit the sheets, make sure your bedroom is dark, keep outside noise down, and turn down your thermostat to around 65 degrees.
Ghrelin, the Appetite Gremlin
In contrast to leptin, ghrelin acts as an appetite stimulator. It's released primarily in the stomach, and when elevated, sends a hunger signal to your brain letting you know it's time to eat. After a meal, you can expect ghrelin levels to return back to baseline within three hours.9
Factors like age, gender, BMI, blood glucose levels, insulin levels, leptin levels, and growth hormone (GH) have been shown to affect ghrelin levels. Leptin itself, for example, can help reduce ghrelin.
Furthermore, if you often find yourself feeling full after a tough workout, it could be because of an increase in GH, which can help dampen hunger and food intake by reducing circulating levels of ghrelin.
The Hungry Games
Put simply, ghrelin makes you feel hungry. Why is perceived hunger so important? Because research has highlighted hunger as a compounding factor in the reasons many diets fail.10
Studies have repeatedly shown increases in ghrelin levels following calorie-restricted weight-loss diets. One study out of the New England Journal of Medicine showed a 24 percent increase in ghrelin levels following a six-month weight-loss diet.11 In a more recent study, researchers from the University of Oklahoma investigated a male bodybuilder during a six-month prep phase and witnessed around a 40 percent increase in ghrelin levels after six months of dieting!12
If you continuously diet or have dieted several times in the past, it's likely that your baseline ghrelin levels are elevated. This could be bad news if you want to stay lean year-round or diet again in the future.
Fight the Ghrelin Gremlin
While the research on ghrelin and diet is limited, recent studies have shed some light on potential dietary strategies that may help to control your appetite and fight the grehlin gremlin.
Supplementing with around 20 grams of oligofructose—a subgroup of the fiber known as inulin—per day split into small doses with each meal may help decrease ghrelin levels, energy intake, blood glucose, and insulin levels.13
Eating higher-protein meals, which are well-known for increasing satiety through several different mechanisms, can help reduce ghrelin levels.7
When dieting, following a high-fat, low-carb (ketogenic) plan may help you control appetite and reduce hunger by keeping ghrelin levels low.14
Short calorie-cycling diets may be a novel strategy to help control some of the metabolic adaptions to weight loss. For example, prolonged dieting reduces leptin and increases ghrelin. By doing shorter blocks of dieting interspersed with higher-calorie blocks, it may be possible to offset some of these adaptations.
This is one of the mechanisms behind the success of weekly high-carb and calorie refeeds. However, it is likely that one would need to refeed for several days in a row to impact ghrelin.15
A sensible approach to calorie cycling may be a 4- to 6-week dieting phase with a 1- to 2-week period at caloric maintenance. If your maintenance calories are set at 2,700, you'll likely be consuming around 2,200 calories during your dieting phase before returning back to 2,700 for a couple weeks to give your body a break.
Along with supporting leptin and ghrelin levels, this strategy may also provide psychological benefits. By breaking your diet into smaller chunks, it becomes easier to focus and adhere to, compared to a 12-week (or more) continuous diet.
One of the few studies on this topic to date investigated minicycles of 11 days dieting and 3 days at maintenance versus continuous dieting.16 Despite total calorie intake being the same between groups, the group that dieted for 11 days and maintained for 3 days lost more weight! Interestingly, these individuals even kept the weight off during the maintenance phase.
Master Your Appetite Hormones
Both leptin and ghrelin levels are key for weight management and successful dieting. Yo-yo dieting will most likely have a long-term negative impact on hormones, body composition, and general health. To avoid the vicious cycle of losing weight and then regaining it, plan in periods of energy maintenance or refeeds. These can be small periods of 3-4 days every two weeks or longer, or one-week periods every 4-6 weeks.
While dieting may feel hard, research shows the maintenance period afterward may be even harder! Make sure your post-diet plan is as optimal and effective as the actual diet itself. Aim for 20-30 grams of protein each meal, and don't ditch the gym. Exercise is key!
Applying the strategies listed above will help you maintain leptin and ghrelin health, but it's critically important that you plan your diet ahead of time, set clear goals, and be patient with the process. If you're going to try cyclical dieting to help your leptin and ghrelin levels, give yourself plenty of time.
- Klok, M. D., Jakobsdottir, S., & Drent, M. L. (2007). The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Obesity Reviews, 8(1), 21-34.
- Lindqvist, A., de la Cour, C. D., Stegmark, A., Hakanson, R., & Erlanson-Albertsson, C. (2005). Overeating of palatable food is associated with blunted leptin and ghrelin responses. Regulatory Peptides, 130(3), 123-132.
- Pelleymounter, M. A., Cullen, M. J., Baker, M. B., Hecht, R., Winters, D., Boone, T., & Collins, F. (1995). Effects of the obese gene product on body weight regulation in ob/ob mice. Science, 269(5223), 540-543.
- Münzberg, H., Björnholm, M., Bates, S. H., & Myers Jr, M. G. (2005). Leptin receptor action and mechanisms of leptin resistance. Cellular and Molecular Life Sciences, 62(6), 642-652.
- Jung, C. H., & Kim, M. S. (2013). Molecular mechanisms of central leptin resistance in obesity. Archives of Pharmacal Research, 36(2), 201-207.
- Reseland, J. E., Anderssen, S. A., Solvoll, K., Hjermann, I., Urdal, P., Holme, I., & Drevon, C. A. (2001). Effect of long-term changes in diet and exercise on plasma leptin concentrations. The American Journal of Clinical Nutrition, 73(2), 240-245.
- Weigle, D. S., Breen, P. A., Matthys, C. C., Callahan, H. S., Meeuws, K. E., Burden, V. R., & Purnell, J. Q. (2005). A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. The American Journal of Clinical Nutrition, 82(1), 41-48.
- Spiegel, K., Leproult, R., L'Hermite-Baleériaux, M., Copinschi, G., Penev, P. D., & Van Cauter, E. (2004). Leptin levels are dependent on sleep duration: relationships with sympathovagal balance, carbohydrate regulation, cortisol, and thyrotropin. The Journal of Clinical Endocrinology & Metabolism, 89(11), 5762-5771.
- Cummings, D. E., Purnell, J. Q., Frayo, R. S., Schmidova, K., Wisse, B. E., & Weigle, D. S. (2001). A preprandial rise in plasma ghrelin levels suggests a role in meal initiation in humans. Diabetes, 50(8), 1714-1719.
- Hays, N. P., Bathalon, G. P., McCrory, M. A., Roubenoff, R., Lipman, R., & Roberts, S. B. (2002). Eating behavior correlates of adult weight gain and obesity in healthy women aged 55-65 y. The American Journal of Clinical Nutrition, 75(3), 476-483.
- Cummings, D. E., Weigle, D. S., Frayo, R. S., Breen, P. A., Ma, M. K., Dellinger, E. P., & Purnell, J. Q. (2002). Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery. New England Journal of Medicine, 346(21), 1623-1630.
- Rossow, L. M., Fukuda, D. H., Fahs, C. A., Loenneke, J. P., & Stout, J. R. (2013). Natural bodybuilding competition preparation and recovery: a 12-month case study. International Journal of Sports Physiology and Performance, 8(5), 582-92.
- Parnell, J. A., & Reimer, R. A. (2009). Weight loss during oligofructose supplementation is associated with decreased ghrelin and increased peptide YY in overweight and obese adults. The American Journal of Clinical Nutrition, 89(6), 1751-1759.
- Sumithran, P., Prendergast, L. A., Delbridge, E., Purcell, K., Shulkes, A., Kriketos, A., & Proietto, J. (2013). Ketosis and appetite-mediating nutrients and hormones after weight loss. European Journal of Clinical Nutrition, 67(7), 759-764.
- Dirlewanger, M., Di Vetta, V., Guenat, E., Battilana, P., Seematter, G., Schneiter, P., ... & Tappy, L. (2000). Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. International Journal of Obesity, 24(11), 1413-1418.
- Davoodi, S. H., Ajami, M., Ayatollahi, S. A., Dowlatshahi, K., Javedan, G., & Pazoki-Toroudi, H. R. (2014). Calorie Shifting Diet Versus Calorie Restriction Diet: A Comparative Clinical Trial Study. International Journal of Preventive Medicine, 5(4), 447.