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Hormones have become a common scapegoat for weight loss woes.
The scale won’t budge? Cortisol must be the culprit.
Heard that insulin blocks fat loss? Maybe it’s time to cut carbs.
There’s no doubt that hormones play a huge role in our physiology and behavior. They regulate countless processes, from inflammation and tissue repair to appetite, metabolism, and fat storage.
That said, no single hormone can be blamed for a failed diet. In the end, no hormone can override the core requirement for weight loss: a calorie deficit.
In this article, we’ll explore how hormones influence weight, how dieting affects them, and how you can modify your diet to keep hormones balanced for better weight management.
Let’s clear up a common misconception: if you consistently consume fewer calories than you burn, you will lose weight–period. No hormone can negate this biological fact.
What hormones can do, though, is make it harder to achieve a calorie deficit. Hormonal imbalances can impact appetite and energy expenditure. And losing weight can feel like an impossible task when you’re constantly battling hunger, cravings, and a sluggish metabolism.
Four hormones, in particular, are key players in energy balance and body weight regulation: insulin, cortisol, ghrelin, and leptin.
Produced by the pancreas, insulin helps regulate blood sugar by enabling cells to absorb glucose, amino acids, and fatty acids. Elevated blood sugar levels–often resulting from carbohydrate consumption–most notably increase insulin levels, though they also rise in response to protein intake.
Insulin lowers blood sugar and supports energy storage by stimulating fat deposition and inhibiting fat breakdown. However, despite what low-carb zealots may claim, insulin alone will not lead to fat gain in the absence of a calorie surplus.
And insulin isn’t just about fat storage. This hormone plays a critical role in muscle repair and growth, helping replenish glycogen stores, suppressing muscle breakdown, and providing muscle cells with amino acids. These anabolic effects may explain why low-carb and keto diets are likely suboptimal for maximizing muscle gain.
In addition, insulin supports satiety and boosts energy expenditure, which is overall advantageous for those looking to lose weight. But without adequate insulin sensitivity–a frequent issue in individuals with obesity–insulin’s effects are diminished, which can perpetuate the problem of weight gain. Still, given the same calorie deficit, those with insulin resistance experience similar weight loss compared to those without it.
Cortisol, secreted by the adrenal glands, is the body’s primary stress hormone. Whether triggered by a hectic day, a tough workout, or low blood sugar, cortisol helps mobilize energy by breaking down stored fat and muscle tissue.
In short bursts, cortisol can be beneficial–it helps fuel your body during demanding (and sometimes life-threatening) situations. Yet, when cortisol levels remain elevated over time, it can become problematic. Whereas acute cortisol release enhances energy expenditure, chronically high cortisol can slow metabolic rate due to muscle loss and reduced thyroid hormone. What’s more, elevated cortisol can heighten hunger and cravings for calorie-dense comfort foods, leading to overeating. Such changes are a recipe for weight gain, particularly in the abdominal region.
Known as the “hunger hormone,” ghrelin is primarily secreted from the stomach when it’s empty or when blood sugar is low to stimulate appetite and eating. Ghrelin also reduces energy expenditure and fat burning. Not surprisingly, high ghrelin levels encourage fat gain and are linked to weight regain after dieting.
Made mainly by fat cells, leptin reflects your body’s energy availability and fat stores. Leptin levels are lower in a fasted state but rise upon feeding, with higher levels supporting satiety to prevent overeating. Beyond its role in satiety, leptin increases energy expenditure and fat breakdown while inhibiting fat storage.
Individuals with excessive body fat (i.e., overweight or obesity) have higher leptin levels than their lean counterparts. Nonetheless, as with insulin, these high levels are accompanied by less sensitivity to the hormone’s actions, which tends to exacerbate weight gain.
While each hormone has its own unique role, they don’t operate in isolation. These hormones interact dynamically, shaping the body’s energy balance and composition.
For example:
Understanding how these hormones work together is crucial for anyone aiming to lose weight.
As you create a calorie deficit, your body adjusts by slowing your metabolism and ramping up hunger to resist further weight loss. These metabolic and hormonal adaptations are part of the body’s survival mechanism.
Here’s how the four hormones we’ve discussed change with weight loss:
Though these hormonal and metabolic changes protect you during times of famine, they pose a significant challenge when you’re actively seeking to shed pounds.
*Cortisol spares fat in the abdominal region. **Acute cortisol release increases energy expenditure, whereas chronically high cortisol can decrease it.
The best way to balance your hormones is to maintain a healthy body weight and composition–and the best way to do so is by controlling your food intake to avoid overeating. When it comes to weight loss and management, a wide variety of diets are effective if you simply stick to them. Find a way of restricting your calorie intake that feels least restrictive to you. And there’s no need to shun entire foods or food groups. In fact, a flexible approach to dieting, in which any food is acceptable in moderation, tends to be more sustainable. In contrast, more rigid dieting is associated with disordered eating and higher BMI. Tracking your macronutrient intake on the Carbon app provides the most straightforward way to control your energy balance, weight, and hormone health.
Extreme calorie deficits lead to more severe metabolic adaptations, tanking your hormone health and chances of long-term adherence. These effects increase the risk of later binge eating and weight rebound, which only further worsen your hormone balance and body composition.
Dietary protein supports hormone balance by suppressing ghrelin, improving body composition, and–as a result–enhancing insulin sensitivity. Even independent of fat mass, muscle is tied to better insulin function due to its glucose-storing capacity.
While carbohydrates are often mistakenly blamed for fat gain and insulin resistance, there’s no good reason to avoid them. For instance, research finds that individuals with type 2 diabetes lose similar amounts of weight when following a balanced, moderate-carb diet compared to a low-carb one. Furthermore, adequate carb intake can provide benefits by reducing cortisol and stimulating leptin release. Consuming fiber in the form of complex carbohydrates is also a significant satiety-booster that helps improve insulin sensitivity and suppress ghrelin.
The quality of dietary fat you consume can cause chronic inflammation, which impairs both insulin and leptin sensitivity. More specifically, saturated fats exert pro-inflammatory effects and have been linked to insulin and leptin resistance. Replacing saturated fat intake with monounsaturated or polyunsaturated fats can help ameliorate this impact on insulin and blood sugar levels. Anti-inflammatory properties of omega-3’s may also implicate them in improving insulin sensitivity, though their effects on leptin are less clear.
A popular hormone-balancing strategy omitted from the above list is the use of refeeds during a fat loss phase. Refeeds involve temporarily increasing calorie intake (usually through carbohydrates) to maintenance levels or higher for 1–3 days. Though they provide short-term psychological relief to boost dietary adherence in some, evidence supporting refeed effectiveness is limited. Overall benefits of multiple-day refeeds on lean mass retention, metabolic rate, and weight loss is fairly modest.
Hormonal imbalances can indeed make weight management more challenging, but they can’t override a consistent calorie deficit. Rather, hormones influence how difficult it is to achieve (and sustain) that deficit—mostly by affecting hunger, energy expenditure, and fat storage. By understanding how insulin, cortisol, ghrelin, and leptin work—and by crafting a dietary approach that keeps them in check—you can lose weight more seamlessly and, most importantly, keep it off.
Looking to master your macros and enhance hormone health? Carbon Diet Coach offers a science-backed approach to help you do just that. Download the app now and see the difference for yourself.
