Have you ever wondered if there is more to weight loss than just eating less? If you're struggling with weight loss, have you ever wondered if it's more than just because you aren't trying hard enough?
There are several appetite hormones that make weight loss more complex an issue than we might initially think it to be. Their role is significant enough to likely make weight loss a matter of more than just willpower. We are learning more and more about appetite and satiety hormones. The first of them- leptin - was discovered relatively recently (in 1994).
Leptin - the "fullness hormone"
Leptin is a hormone made by fat (or adipose) tissue. In fact, the more body fat you have, the more leptin hormone you have. Leptin has a major role in controlling (or decreasing) food intake and body weight. When there are proper amounts of it and it functions properly, it can prevent weight gain and control body fat.
You would think that since more body fat is associated with more leptin then more leptin in obese individuals makes them feel more naturally full, right? Well, it doesn't always work that way.
In the case of obesity, the body becomes more resistant to leptin. So even though you may have plenty of leptin circulating, it just can't get its job done to make you feel full. Why? In leptin resistance, the hormone doesn't reach its target - the hypothalamus in the brain. The brain never gets the message that you're full! The brain still thinks leptin levels are low and the body is still hungry. As a result, the vicious cycle continues:
> brain sends out signals to the body to increase food intake
> eat more
> store fat
> weight gain
> more body fat increases leptin made by fat cells
> excess fat interferes with proper leptin function (even though there's plenty of leptin around)
> brain thinks you are low on leptin and, thus, starving
> eat more
> store fat
> weight gain
> and on and on ....
Why does this happen?
A lot of it has to do with inflammation. As we know, fat tissue is not inert tissue. It is metabolically active. It produces all sorts of chemicals, including large numbers of inflammatory chemicals (called cytokines). These inflammatory chemicals can block the effects of leptin.
Our understanding of leptin sensitivity is still not complete, though. There are several explanations for why the leptin "I'm full!" signal to the brain is interrupted. What we do know is that, regardless of the actual mechanism involved, when body fat reaches a certain high level, your appetite signals and hormones are not functioning right anymore. The ones that are supposed to make you feel full end up leaving you feeling hungrier.
Therefore, to answer the initial questions brought up in this article, yes! There are other factors involved in successfully losing weight. There are many, complex factors that influence weight loss.
How to Boost Leptin Sensitivity
So, how can you increase your body's sensitivity and response to leptin? Whatever you do, do not get discouraged by leptin resistance. It is still possible to lose weight and keep it off. Proper nutrition, regular physical activity, and other lifestyle changes are still the hallmark of successful weight loss efforts.
Research on increasing leptin sensitivity is still relatively new but the body of evidence is growing. Until our understanding grows, there are several key strategies to start with:
1. Sleep enough. Inadequate sleep leads to less leptin and even more of the hunger hormone - ghrelin. Generally, 7 to 8 hours is considered adequate.
2. Stick to regular physical activity. View exercise as more than just for burning calories. It can also help reduce leptin resistance. How? It has to do with that its anti-inflammatory effects. As mentioned earlier, inflammation appears to block leptin signaling to the hypothalamus in the brain. Aim to get at least 30 minutes of exercise most days of the week. Check with your MD before starting an exercise program.
3. Work to reduce your sugar intake. Avoid added sugars or added sweeteners.
4. Eat foods that are more nutrient-dense and less calorie-dense. For example, a good strategy is to fill half your plate with plenty of non-starchy vegetables. Although it's a higher volume of food, it carries less calories per bite.
5. Find enjoyment in other activities. When a food craving occurs, find an alternative activity - reading, biking, calling a friend, listening to music, taking a walk, or anything else that provides pleasure. Give your craving an hour - if you give it time, it may disappear.
6. Reach for more leptin foods, as highlighted in the next article in this newsletter.
References
Benedict C, Axelsson T, Söderberg S, et al. Fat mass and obesity-associated gene (FTO) is linked to higher plasma levels of the hunger hormone ghrelin and lower serum levels of the satiety hormone leptin in older adults. Diabetes. 2014;63(11):3955-3959
Friedman JM, Halaas JL. Leptin and the regulation of body weight in mammals. Nature 1998;395:763–770pmid:979681
Friedman JM, Mantzoros CS. 20 years of leptin: from the discovery of the leptin gene to leptin in our therapeutic armamentarium. Metabolism. 2015;64(1):1-4.
J Sleep Res. 2010 Dec;19(4):552-8
Prz Gastroenterol. 2014;9(2):69-76.
Schwarz NA, Rigby BR, La Bounty P, Shelmadine B, Bowden RG. A review of weight control strategies and their effects on the regulation of hormonal balance. J Nutr Metab. 2011;237932.
