Appetite suppressants control hunger – which can be the key to weight loss for many. No matter how hard you exercise, if you don’t properly control your energy intake you’ll find it tough to reach your fat loss targets.
Weight loss drugs, pills and supplements can generally be separated into three categories.
Increased thermogenic effect – these are said to elevate heat production, metabolic rate and fat oxidation. Reduced nutrient absorption – inhibits the take up of calories from fats or carbohydrates. Decreased appetite – some nutrients are said to decrease hunger, making it easier to reduce energy intake.
1 Appetite suppressants help control hunger. Appetite suppressants either indirectly or directly alter brain chemistry so that you feel satiated for longer periods of time when compared to other foods. And when you eat less you can achieve your calorie deficit much easier.
Natural appetite suppressants have been around for hundreds of years. Herbal laxatives have been used in Ayurvedic medicine for centuries, and even the Greek physician Soranus of Ephesus was said to have introduced various elixirs to stop his patients from overeating.
Some of these natural nutrients are said to help weight loss by boosting satiety and reducing feelings of hunger, without a stimulatory effect. Common suppressants include: glucomannan, hoodia gordonii, chromium, forskolin, guar gum, ginger, piperine, capsaicin.
Currently, commercially-available appetite suppressants are a huge market in the weight loss industry. Although they’ve been used in traditional medicine for many years, the supplement industry continues to use these more and more.
To date, an ever-increasing number of appetite suppressant remedies are being manufactured. Some use the same kinds of herbal nutrients or foods, while others introduce less well-known blends of ingredients.
Prescription drugs can also act as appetite suppressants. When more modern appetite suppressant medicine came along in the early nineteen hundreds, drugs such as amphetamines became popular – along with prescription appetite suppressant drugs much later on that decade (1).
The most common prescription appetite suppressants can be split into two broad categories (2). These include:
Those that act directly on catecholamine pathways: Amfepramone, Phentermine, Mazindol, Phenylpropanolamine.
Those that act directly on serotonin pathways: Dexfenfluramine, Fenfluramine.
2Appetite suppressants may increase the satiety response. Some appetite suppressants do decrease hunger signals, increase feelings of satiety and ultimately, the number of calories you consume. Presuming you manage to burn more off than you eat, you will indeed lose weight.
Appetite is controlled by a region of your brain called the hypothalamus (3).
As the master computer of the body, it is responsible for telling you exactly when you need food the response of course that you begin to feel hungry – after all, being able to ‘forage’ an energy source is an important aspect of energy homeostasis.
The hypothalamus helps us maintain body weight around a set point, and avoid all of the pitfalls that comes with low energy intake (malnourishment, illness, death).
However, with so much food available in the modern climate, many people take foraging to the extreme, choosing to overeat an abundance of calories. Which of course leads to weight gain.
And this is where appetite suppressants come in. Purely as a way to manage the foraging effect and overeating.
3Appetite suppressants act on hunger hormones and neurotransmitters Appetite refers to the desire for food intake. Hunger itself relies on complex interaction between the central nervous system, hormones and the gut.
The hypothalamus controls hunger and satiety using hormones. The most important and relevant ones are leptin, ghrelin, CKK, PYY and GLP-1.
Appetite suppressants are said to improve weight loss by changing the way in which these hormones work. Some also act on noradrenergic and dopaminergic receptors (alongside hormones) to produce satiety (4)
They essentially hijack satiety and appetite hormones and interrupt the hunger signals when you should normally feel hungry, helping you reduce overall food intake.
4Research shows that prescription appetite suppressants can increase weight loss. There has previously been research showing appetite suppressant drugs can lead to significant weight loss by decreasing overall energy intake.
For example, a study in the Lancet (5) found that a type of monoamine-reuptake (MOA) inhibitor manufactured as an appetite suppressant resulted in average in 4-5 kg of weight loss when used long term.
One report suggested that weight loss was greater with appetite suppressants when compared to placebo (6). It also stated that net weight loss varied from 2 kg to 10 kg and this could be sustained for up to 36 months.
MOA reuptake inhibitors are said to cause weight loss by selectively uptaking neurotransmitters such as 5-HT, noradrenaline and dopamine. This in turn directly enhances appetite suppressing effects on the central nervous system and the associated hormones (7).
5Appetite suppressants might also burn more calories. Some appetite controlling drugs may also have an effect on total daily energy expenditure.
The now banned appetite suppressant sibutramine (8) was said to be able to prevent the drop in basal metabolic rate that is often seen during weight loss.
It did this by activating a protein involved in eating behaviour called MCR-4 (9).
Some tentative evidence also suggested that sibutramine also increased thermogenesis too (10).
According to some reports, “when used appropriately, appetite suppressants can be of real therapeutic benefit” (11).
6Natural hunger suppressants are often added to over-the-counter products, but may not be as effective. Appetite suppressing nutrients are often added to ‘fat burner’ supplements.
Natural ingredients such as caffeine, capsicum, ginger, piperine, glucomannan and grapefruit are often added to pharmaceutical supplements for example as a way of boosting satiety.
There are some clinical trials that have reported benefits of these nutrients.
For example, one study found that capsaicin offered modest improvements to both satiety and food intake choices in 24 men and women (12).
Specifically, ingesting capsules containing 0.9 g of red pepper (0.25 g capsaicin) increased satiety ratings from 689 to 757 mmh in the men and from 712 to 806 mmh in the women, both (P<0.01).
And in another study, ginger was found to reduce feelings of hunger too (13).
It’s worth noting though that the research on natural appetite suppressants isn’t unequivocal.
For example, a study published in the European Journal of Nutrition (14) found that adding the compound capsaicin to meals did not increase satiety, energy expenditure or had any effect on hunger hormones.
Likewise, a clinical study analyzing the safety and efficacy of glucomannan found that even though it is added to fat burner supplements as a appetite suppressant, it did not significantly alter body composition, hunger/fullness, or lipid and glucose parameters (15).
Appetite suppressants have been implicated in a number issues, including side effects and adverse reactions.
1Appetite suppressants can cause mild to moderate IBS like effects. These include: nausea, sickness, gastrointestinal discomfort, blurred vision, sleeplessness, insomnia and lack of energy, constipation, diarrhea and trouble urinating, dry mouth, irritability, elevated heart rate, mood changes and breathing difficulties.
There have also been cases of more severe adverse reactions reported too.
2Appetite suppressants can increase the risk of primary pulmonary hypertension. A prospective case-controlled study found that there was a clear and significant correlation between appetite suppressant, ‘anorexia drug’ fenfluramine and pulmonary hypertension (16).
The odds of suffering from this serious medical condition were said to more than double when taken for over three months.
3Prescription appetite suppressants increase risk of cardiac valve disorders. Both fenfluramine and phentermine have at one time or another been implicated in higher risk stratification for cardiac valve disorders – in particular aortic and mitral valve insufficiency.
One study reported that pharmacological effects of these drugs elevated the risk of these cardiac-based illnesses (17).
The results showed that in those who had taken either fenfluramine and phentermine for four or more months, the cumulative incidence of idiopathic cardiac-valve disorders was 35.0 per 10,000 subjects.
And in a case study of a 28-year old male, an over-the-counter MAO inhibitor was seen to cause ‘hypertensive crisis’ after ingestion (18).
4Commercial diet pills containing appetite suppressant ingredients can increase blood pressure. One case study found that when a patient submitted to the ER ingested a commercially available diet pills containing the appetite suppressant phenylpropanolamine, the inhibition of prostaglandins caused by the drug resulted in extreme hypertension (19).
5Appetite suppressants have certain drug interactions. Oral appetite suppressants can interact with some prescribed medications such as MAO inhibitors (linezolid and furazolidione in particular)
They can also interact with other types of weight loss medicines, as well as supplements.
Because the term ‘appetite suppressant’ covers a group of drugs and supplements rather than one individual product there is no clear, catch-all dosage.
For prescription drugs, the majority of manufacturers suggest dosage instructions of 25-50 mg once daily to begin with. This would increase to 50 mg one to three times per day once initial safety had been established.
Drugs such as phentermine and dexfenfluramine are recommended at small doses of 15 mg in most cases. At no point are prescription appetite suppressants recommended to be taken at doses above 250 mg per day.
For natural compounds, dosage also varies. For example, capsaicin is often recommended to be effective at 150 mg in healthy adults, and glucomannan at around 2g.
Is nicotine an appetite suppressant? Yes, and its a big reason smokers are often not overweight.
Can you shrink your stomach to control appetite? Once you are an adult, your stomach pretty much remains the same size — unless you have surgery to intentionally make it smaller.
Do appetite suppressant pills really work? Yes, appetite suppressant pills with proper dosages and ingredients can curb hunger.
Are there natural appetite surpassing foods? Yes, there are. Spinach is a source of thylakoids, which have been associated with levels of leptin, the hormone that signals you to “stop” eating. Flaxseed is rich in two natural appetite suppressants: omega-3 fats and fiber. Fiber from flaxseed can keep us satisfied and full, without contributing any calories.
Do appetite suppressant patches work? There is not enough scientific evidence to prove appetite suppressant patches do work.
Are appetite suppressants dangerous? When used properly, they are not dangerous.
Can I take appetite suppressants while breastfeeding? Taking appetite suppressants while breastfeeding is an ill-advised way to lose baby weight. … While you’re breastfeeding, your need for calories also increases so you can give your body — and that of your baby — adequate daily nutrition.
Appetite suppressants claim to help with weight loss by reducing hunger and increasing satiety.
They may also have a direct effect on weight loss in some cases by increasing thermogenesis and offsetting a drop in metabolic rate while dieting.
Research indicates that prescription appetite suppressants may help with weight loss. However the number of case reports detailing adverse reactions and mild-serious side effects is concerning.
There have been a number of attempts to make a prescription appetite suppressant that is free from side effects. Unfortunately, manufacturers have failed so far.
Natural herbs, foods and nutrients have been shown to enhance weight loss in some studies, however the results rarely consistent.