Throughout the US and the world, people are trying to lose weight. In fact, nearly 50% of all adults in the US have tried to shed pounds in the last year. Among them, almost 9 million have tried using a supplement to lose that weight. So it’s fair to ask: does using a supplement actually work?
It’s difficult to find accurate studies of specific supplements, because in the scientific community there is always the risk of bias–is the supplement maker funding the study, for instance? So I’ll try to answer this question as factually as I can, by looking at some of the most common metabolism-boosting supplement ingredients to determine if the really work.
what you need to know
Rundown of Scientific Studies
We’ll cover a lot of science in this section, but don’t worry. I’ll keep the key points in bold type, and I’ll stick to what you absolutely need to know, and I’ll organize this by ingredient type. We’ll kick things off with Caffeine, perhaps the most common weight loss supplement ingredient of all time.
Caffeine (Extract)
Most clinical trials of caffeine differentiate it from coffee, Green Coffee, and Green Tea because caffeine extract is usually how it’s used in supplements; manufacturers rarely make gallons of coffee and then put that into a pill.
Most studies of caffeine have focused on its thermogenic properties. These are well-researched, and the correlation is strong. When we take in caffeine, it literally heats up parts of our body, to the point where we actually begin to burn more calories, even at rest.
But if you’re actively exercising to lose weight, then the benefits of caffeine are even greater. One meta-analysis of studies found that caffeine improves exercise performance across all exercise types–boosting the body’s ability to process blood sugar as fuel.
Lastly, there is limited but compelling evidence that caffeine can lead to mild insulin resistance (IR). There isn’t enough science out there to suggest that all caffeine intake leads to insulin resistance; only that if you already have IR or are diabetic, consult your doctor before taking supplements with high caffeine doses.
A Note of Caution–Insulin Resistance
This process is well-known to any diabetic reader, but for everyone else, here’s a quick summary of how insulin resistance can lead to weight-gain.
When we eat nearly any food, our bodies break it down into forms of sugar and put that sugar into our bloodstream. Then, our pancreas produces insulin; insulin tells our cells to take that sugar up and burn it as fuel. When we are resistant to that insulin signal, our cells don’t take up the blood sugar; this leads to our bodies storing the sugar as fat, and to our cells sending the hungry signal to our brains. Even though we’ve eaten, our cells never got the signal to take up the blood sugar, so they never got the fuel.
Capsaicin
Like caffeine, Capsaicin has huge thermogenic properties that can help burn fat and boost the metabolism. Importantly, these data have been looked at through the individual and the meta-analysis lenses: Capsaicin helps you lose weight.
But what about metabolism, on the whole? Results here have been more mixed, especially when it comes to sugar (glucose) metabolism. While some clinical trials have proven chemically that Capsaicin can boost sugar metabolism, trials with actual participants have been mixed. For instance, one study showed higher insulin in the system after taking Capsaicin, a possible indication that it can lead to insulin resistance.
Fiber
There’re a lot of jokes about bran muffins, but the fact is that fiber is one of the secret weapons of the fit and healthy. Study after study has shown that high fiber diets can improve weight, body fat, and yes, improve metabolic health, including better management of sugars and fats in the bloodstream.
Not only can fiber help us process these sugars better during digestion, but multiple studies have proven that fiber helps with insulin resistance. This in turn helps regulate how much sugar there is in our cells versus our bloodstream, and can even lead to lower appetites.
Soluble or Insoluble?
The question rages, I’m sure, in all your discussions with friends and family. I’ll make this quick. Insoluble fiber has the most health benefits, including helping to prevent Type-II Diabetes. Soluble fiber is good, insoluble is great.
Glucomannan
Glucomannan has become a popular ingredient as the fiber-of-choice in many supplements. In fact, Leanbean and Hourglass Fit, two of the very best fat burners for women, both use glucomannan to achieve appetite control and metabolism boosting benefits.
There is pretty solid science to support that glucomannan has multiple metabolism benefits, and that those only increase with diet modification (eating less sugars and fats). This research has led the FDA to officially consider glucomannan a recognized dietary fiber; wherever you see a benefit of dietary fiber, that applies to glucomannan as well.
Choline
Of all the ingredients we’ve discussed so far, none are as helpful for your metabolism as Choline. That’s because Choline is absolutely essential for metabolic processes. Our bodies literally cannot even metabolize food without Choline’s help along the way. Despite being necessary for metabolic health, official data indicate that:
- men get 26.9% less Choline than they need, and
- women get 34.5% less than they need.
Because one of Choline’s functions is to create healthy cell walls, it is essential for gut-microbe health. Finally, a study of over 3,000 Canadians found that Choline intake is associated with lower body fat, lower weight, more lean muscle, and better metabolism.
Green Tea Extract and Green Coffee Extract
I’ve decided to give these two supplement ingredients their own section because they both have primary outcome benefits different than just their containing caffeine. Starting with Green Tea Extract (GTE), a meta-study found that even without caffeine, the catechins in GTE can reduce blood sugar. In addition to both of these individual benefits of GTE, it’s even more effective with additional caffeine. In one 12-week study, GTE with added caffeine was more effective than either ingredient alone in decreasing body weight and waist circumference.
Green Coffee, meanwhile, has its own hidden benefit that’s not present in caffeine or other coffee forms: Chlorogenic Acid. Chlorogenic Acid is literally cooked away when coffee beans are roasted, but Green Coffee is one of the most abundant sources of Chlorogenic Acid in the world.
The exact mechanisms of Chlorogenic Acid are still being researched, but one thing is already clear. Chlorogenic Acid plays a key role in sugar and fat metabolism, and it cannot be found in other coffees.
Final Thoughts
Weight Loss supplements account for a third of all supplement sales; before we buy one more bottle, as consumers we need to know if they actually work. While there are many functions that a weight loss pill can promise to fulfill, one of the most important is whether it can increase our metabolism.
It’s not really feasible to find scientific analyses of every supplement on the market. But because so many of the best supplements use a similar core of ingredients, we can examine some of these for efficacy. Among those I’ve researched, the science is reasonably reliable that caffeine, fiber, choline, and capsaicin really can boost metabolism.