The Surprising Link Between Chronic Inflammation & Obesity—Plus What You Can Do About It
Chances are, if you have put on a few pounds, the cause is deeper than eating too much junk food or skipping one too many workouts. Chronic, low-grade inflammation that swells in the body is to blame for this gain. And the relationship is cyclical. Weight and inflammation go hand in hand, and working to maintain a healthy weight through diet, exercise, sleep and stress management can help tame inflammatory markers as well.
Inflammation, however, comes in two varieties: acute and chronic. Most of us are accustomed to acute inflammation, such as after sustaining an injury. This temporary response doesn't serve as a catalyst for serious health conditions but actually protects the body.
Chronic inflammation manifests as a slow burn in the body. "Inflammation is designed so once your body needs some healing, inflammation rushes in, but it's only supposed to be short term. Chronic inflammation is more subtle, and it's caused by irritation in the body," says Carolyn Williams, Ph.D., R.D., author of Meals That Heal. "And that may be environmental things, that may be food-related things, that may be stress, that may be lack of sleep. Just about any kind of irritation to the body can trigger subtle inflammation." Williams compares chronic inflammation to a fire in the body that will continue to grow without intervention. Research suggests that reducing chronic, low-grade inflammation may even be as crucial a component as diet and activity, Williams says. And the relationship goes both ways. "Among people who are overweight or obese, immune cells start to infiltrate that fatty tissue. That in itself is thought to be part of what drives that chronic inflammation," says Caroline Childs, a lecturer in nutritional sciences at the University of Southampton in the U.K. "So people who are overweight or obese may be more likely to be experiencing chronic inflammation. Whether that is causing them to gain weight or a result of having gained weight is a bit hard to unpick." A 2018 study in the journal Clinical Nutrition, for example, found that weight loss in obese and overweight subjects "is a determinant factor for reducing the level of pro-inflammatory markers."
Leptin is one significant influence in this cyclical relationship between weight and inflammation. High levels of chronic inflammation can detrimentally increase leptin in the body. A hormone released from the body's fat cells, leptin communicates with the hypothalamus to regulate food intake and energy use. Since leptin comes from fat cells, it is directly related to body fat. Sometimes referred to as the "satiety hormone," leptin inhibits hunger and regulates the body's energy balance, which keeps you from feeling hungry when your body doesn't need any energy. Someone who is obese, however, will have too much leptin in their blood, which can cause an aversion to the hormone in what is known as leptin resistance. This, in turn, makes the body want to keep eating. "So your body isn't getting proper feedback about appetite and when to stop eating and when you're satisfied," Williams says. Levels of leptin that result from weight loss can also increase appetite and cause more food cravings, which can make further weight loss more difficult. Excess leptin in obese individuals is considered a contributor to low-grade, chronic inflammation. This can lead to higher susceptibility to chronic conditions, such as cardiovascular disease, type 2 diabetes and autoimmune diseases, such as rheumatoid arthritis. Leptin joins with weight and inflammation to form a damaging cycle.
Inflammation and weight gain also work together in influencing the body's insulin response. A 2018 study in the Journal of Clinical Investigation found that insulin resistance promoted body-fat inflammation in mice. The researchers stated that there is a "chicken and egg" relationship between insulin resistance and inflammation in that "obesity induces insulin resistance . . . which in turn promotes inflammation." This can increase the symptoms and severity of type 2 diabetes. "The problem is that they both fuel one another. Weight gain causes more insulin resistance, insulin resistance causes more weight gain, and then inflammation is at the root of all of them. It's almost like they're just cyclical and build on one another," Williams says.
Sudden or unexplained weight gain, however, might be caused by inflammation in the thyroid, a butterfly-shaped, hormone-secreting gland located at the front of the neck that influences metabolism, growth, development and body temperature. When the thyroid gland becomes inflamed and produces too few hormones, this leads to hypothyroidism, and metabolism slows, causing sudden weight gain. "Your thyroid is going to control a lot of those hormones that affect your metabolism, so any time you have changes in your weight and changes in inflammation, they both alter your hormone fluctuations and the proper balance that all of those are supposed to be in," Williams says.
When it comes to losing weight and taming inflammation, your diet is a crucial factor. "An anti-inflammatory eating approach really benefits everyone, but it should definitely be a component of the way you eat if you're trying to lose weight," Williams says. So how can you ready your plate to fight back against inflammation? Add some color. This includes dark, leafy greens, such as spinach and kale, and vibrant fruits, such as tomatoes, berries and oranges. Additionally, consider swapping red-meat proteins with lean picks, such as chicken and fatty fish, particularly salmon. "Oily fish or omega-3s are the best-understood anti-inflammatory foods," Childs says. "If as individuals we can aim toward eating oily fish once or twice a week, that would be beneficial." Not to fret if you're vegetarian; Childs recommends algae as a plant-based source of these healthy omega-3s. To implement healthful carbohydrates, try using whole-grain bread on for your sandwiches or whole grain pasta with a low-sugar sauce.
Recent research highlights these anti-inflammatory foods as key factors in healthy weight management. A recent study in the European Journal of Nutrition, for example, examined the effect of a legume-based, low-calorie diet on inflammation in overweight and obese participants. The researchers found that consuming four servings of legumes per week reduced inflammatory markers and therefore improved metabolism in the subjects. Additionally, a 2014 review in the Journal of Agricultural and Food Chemistry discussed that eating whole fruits and whole fruit products has shown to mitigate inflammatory markers in some studies. These foods also fall in line with the popularized Mediterranean diet, which emphasizes fruits, vegetables, whole grains, beans, legumes, herbs and spices. It also highlights plant-based and lean proteins.
Childs acknowledges, however, that healthy picks, such as salmon and kale, might not be financially accessible to everyone and recommends more affordable options, such as carrots, peas and apples to achieve the same anti-inflammatory benefits. All these whole foods have similar anti-inflammatory effects. "Focus on getting your calories from real foods," Williams emphasizes, also pointing toward low- and moderate-carb diets that target excess weight and inflammation. These foods and eating pattern can also help balance insulin and glucose levels.
And controlling weight and inflammation isn't just a matter of what you eat; other lifestyle changes have the same close relationship as food to weight loss. "What we're realizing is we tend to think weight is just related to food, but weight loss and inflammation, both are whole-body approaches," Williams says. Williams points to psychological aspects, such as sleep, stress and exercise, as influences for weight control. Lack of shut-eye is one of the most common factors; the Centers for Disease Control and Prevention estimates that 35% of adults don't get enough sleep—at least 7 hours per night.
Though a revamped plate and lifestyle changes can decrease harmful inflammation in the body, you still need small amounts of acute inflammation, such as when you sprain your ankle. The goal is to avoid getting too much of a good thing. "A little bit in the right place is a good thing. We don't want to turn it off completely," says Childs. "I think the challenge is finding the right balance.