Related Terms

• Diet, Dr. Alan R. Hirsch, SENSA®, SENSA® Tastant crystals, SENSA® weight loss system, sensory-specific satiety, sprinkle diet, tastant, weight loss.

Background

• The SENSA® sprinkle diet is a proprietary weight loss system that directs consumers to place SENSA® Tastant sprinkles or crystals on all food before consumption (tastants are any substance that stimulates taste). This method does not involve changing the diet, eating special meals, or restricting food intake. The manufacturer is currently seeking a patent for its product.

• The scientific theory behind the diet is the concept of sensory-specific satiety. According to the company, during eating, taste and smell senses interact with the brain centers for satiety, which tell the body when it has had enough to eat. The manufacturer of SENSA® Tastant sprinkles claims that its product speeds up this process, so that less is eaten but satisfaction is adequate. Scientific evidence, however, suggests that volume of food intake may be the most important part of sensory-specific satiety.

• The manufacturer advices consumers to use one packet of SENSA® Tastant sprinkles over the course of each month, putting them on food daily, and to alternate between the different varieties, formulations, or flavors of sprinkles monthly. SENSA® Tastant crystals come in six different patent-pending scent or flavor combinations.

• Dr. Alan R. Hirsch, a board-certified neurologist and the director of the Smell & Taste Treatment and Research Foundation in Chicago, Illinois, developed the SENSA® product. He is also a faculty member in the Department of Medicine at Mercy Hospital and Medical Center, and an assistant professor in the Department of Neurology and the Department of Psychiatry at Rush Presbyterian St. Luke's Medical Center. He cites three studies on the company website that support the use of SENSA®.

• The media have featured interviews with Dr. Hirsch, who admits that the patients who were studied monitored their own weight and reported their results to the investigators. This suggests that there was no independent verification of the weight changes reported by the patients. It is unclear if other causes of weight loss were investigated or evaluated. Additional information that might clarify these points is currently unavailable.

Diet

• Technique: According to the manufacturer of SENSA®, the SENSA® sprinkle diet does not require an individual to eat special meals or to limit food intake. The only requirement is that the SENSA® Tastant crystals be sprinkled on all solid food before it is eaten. Only a light dusting is required, so that one packet is expected to last an entire month. Spraying dry foods lightly with water before eating is advised to help the SENSA® crystals adhere to the food.

• The company website does not recommend a specific duration for the diet, but sells the product in installments of six packets, enough for six months, and states that the product may be used for additional time as desired. The implication from the manufacturer is that ongoing use of the SENSA® Tastant crystals may be necessary to maintain weight loss.

• The onset of weight loss may occur in the first month, but the company states that there is no typical timeline.

• Availability: The company sells SENSA® Tastant crystals in packets designed to last for about one month.

• Preparations: There are six different flavors of crystals, which are designed to prevent developing a tolerance to the effects of any one preparation. Therefore, each formulation is meant to be used for only one month at a time. The website states that use beyond six months requires the customer to restart with the formulation used for the first month. Three formulations are savory and three are sweet. Some of the flavors have been described in consumer magazine accounts as mimicking cheese, cocoa, horseradish, and banana.

• Consulting health professionals: Although the manufacturer's website states that use of the product is safe, it encourages consulting a physician or medical professional before using SENSA® or beginning any weight-loss plan, whether or not the person has any current medical concerns.

• Weight gain: According to the manufacturer's website, weight gain at the beginning of the SENSA® diet suggests that the person is not yet responding to the hunger signals that are sent by the body. The manufacturer advises individuals to eat slowly and stop eating as soon as there is a feeling of fullness.

Theory/Evidence

• Science of appetite and weight: The factors that control food intake and weight are complex. They include "hunger hormones" such as ghrelin and "satiety hormones" such as leptin. Ghrelin is released by cells in the stomach lining and is associated with increased appetite and hunger. Leptin is released by fat cells and acts on receptors in the brain to inhibit appetite by causing the release and action of yet other hormones. Medical studies suggest that there may also be sensory and psychological components related to upbringing; attitudes towards food; types of food; and where, when, and how food is eaten.

• Theory of sensory-specific satiety: There is significant medical literature on the theory of sensory-specific satiety, which relates to the effects of the type, taste, and variety of food on appetite and the amount of food eaten. The theory behind the SENSA® diet, according to the website, is that by enhancing the sense of smell, the satiety centers in the brain will signal fullness sooner than usual, so that eating will stop earlier, and the food intake will be less than the customary amount. Scientific evidence suggests that the volume of food intake may be the most important part of sensory-specific satiety.

• Clinical studies: The manufacturer of SENSA® describes three studies that suggest that the SENSA® sprinkle may lead to weight loss.

• The first study was an initial pilot study of 108 subjects during a period of six months, in which the SENSA® product was associated with weight loss.

• The second study reported on the SENSA® website enrolled a total of 2,437 subjects who began using SENSA® Tastant crystals. Of this group, 1,436 subjects completed the six-month study and were compared to a control group of 100 people. (It is unclear what happened to the other 1,001 people in the study.) The 1,436 people in the treatment group lost an average of 30.5 pounds, or nearly 15% of body weight, whereas those in the control group lost an average of two pounds. While this study was published in the Journal of Neurological and Orthopedic Medicine and Surgery in 1995, according to the website, this journal is not a part of the mainstream medical literature routinely reviewed by the National Library of Medicine (PubMed).

• A third study, conducted by an independent laboratory, included 83 participants. The participants were randomly assigned to use SENSA® Tastant crystals or a placebo daily for six months. Seventy-three people completed the trial. Participants in the SENSA® group lost an average of 27.5 pounds, whereas participants in the control group gained a half pound on average. This study does not appear to have been published in any impartial journal, which does not permit an independent assessment of the approach or validity of the study and the SENSA® product.

• Neither the company nor Dr. Hirsch claims that the long-term efficacy or safety of SENSA® has been established. There do not appear to be any long-term studies of the effects of the diet or of the weight history of persons once they are no longer following the diet. Therefore, it is unclear if weight loss as a result of using SENSA® is maintained after stopping the regimen.

• Level of evidence: There is currently not enough high-quality evidence available to support the claims for effectiveness made on the SENSA® website. On the contrary, a number of articles during the last decade have noted that studies examining sensory-specific satiety have been contradictory in their conclusions. In some of these studies, increasing the sensory novelty of food appears to increase food intake (e.g., people will eat more fries after tiring of plain fries if they are then allowed to use ketchup).

• Also, fat content has been found to be less influential than flavor in determining when people stop eating, and there does not appear to be a difference between sweet and savory flavors in sensory-specific satiety nor between obese subjects and normal-weight subjects.

• There is also a lack of evidence that enhancing flavor by using SENSA® will increase or decrease total food and total calorie intake through sensory-specific satiety. One study looked at calorie intake based on a range of flavor intensities in lemonade drinks and found that flavor intensity did not appear to influence the amount of beverage consumed.

• Sense of smell: If the sense of smell or taste is impaired, the effectiveness of SENSA® may be diminished. If an individual lacks a sense of smell or taste entirely, the product will likely be ineffective.

• Public response: Aside from news sources reporting on press releases from the company that manufactures SENSA®, there are a number of diet and weight loss websites that have reviewed this weight loss program and expressed skepticism about its claims.

• The U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control and Prevention (CDC) do not mention any information regarding SENSA®.

Safety

• Ingredients: According to the manufacturer, SENSA® Tastant crystals contain soy (in the form of soy-lecithin), unspecified milk ingredients, and natural and artificial flavors. The presence of these ingredients may put a person with a known milk or soy allergy at a higher risk of having an allergic reaction. The company website does not specifically mention food allergies. The exact combinations of the SENSA® blends are proprietary and patent-pending. However, according to the manufacturer, flavors are not derived from meat sources, and they contain no mushrooms, nutmeg, cinnamon, fish, or garlic. The only other ingredients listed are maltodextrin (made up of easily digestible carbohydrates from natural corn starch), tricalcium phosphate, and silica. Since the blends are proprietary and the specific ingredients are not published, there may be a risk of allergy or intolerance to particular ingredients for a given individual.

• Side effects: The summary of the double-blind study cited by the manufacturer states that no test subjects reported negative side effects for either the SENSA® product or the placebo. This claim could not be verified through any third-party source.

• U.S. Food and Drug Administration (FDA) status: Approval by the U.S. Food and Drug Administration (FDA) is not required for SENSA® crystals, because they are considered a food product. The SENSA® ingredients that are listed on the manufacturer's website are on the FDA's Generally Recognized as Safe (GRAS) list. Although some flavors of SENSA® contain soy and milk ingredients, all of the varieties are reportedly meat-free.

• While the company states that the ingredients of SENSA® are safe, they recommend that consumers discuss the use of SENSA® with qualified healthcare professionals.

• Pregnancy and childhood: It is unclear if the product is unsafe in people with any specific medical conditions. It has not been tested in children or pregnant women. Information on the potential risks or dangers has not been described. In addition, a diet program that does not offer advice or encouragement on healthy food choices or on the importance of exercise may be considered incomplete.

Author Information

• This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

1. Brondel L, Lauraine G, Van Wymelbeke V, et al. Alternation between foods within a meal. Influence on satiation and consumption in humans. Appetite. 2009 Oct;53(2):203-9. View Abstract

2. Brondel L, Romer M, Van Wymelbeke V, et al. Variety enhances food intake in humans: role of sensory-specific satiety. Physiol Behav. 2009 Apr 20;97(1):44-51. View Abstract

3. Centers for Disease Control and Prevention (CDC). www.cdc.gov.

4. Havermans RC, Geschwind N, Filla S et al. Sensory-specific satiety is unaffected by manipulations of flavour intensity. Physiol Behav. 2009 Jun 22;97(3-4):327-33. View Abstract

5. Hirsch AR, Gomez R. Weight Reduction Through Inhalation of Odorants. J Neurol Orthop Med Surg (1995) 16:28-31.

6. Macht M. How emotions affect eating: a five-way model. Appetite. 2008 Jan;50(1):1-11. View Abstract

7. Natural Standard: The Authority on Integrative Medicine. www.naturalstandard.com.

8. Olszewski PK, Levine AS. Central opioids and consumption of sweet tastants: when reward outweighs homeostasis. Physiol Behav. 2007 Aug 15;91(5):506-12. View Abstract

9. Remick AK, Polivy J, Pliner P. Internal and external moderators of the effect of variety on food intake. Psychol Bull. 2009 May;135(3):434-51. View Abstract

10. Snoek HM, Huntjens L, Van Gemert LJ, et al. Sensory-specific satiety in obese and normal-weight women. Am J Clin Nutr. 2004 Oct;80(4):823-31. View Abstract

11. Sorensen LB, Moller P, Flint A, et al. Effect of sensory perception of foods on appetite and food intake: a review of studies on humans. Int J Obes Relat Metab Disord. 2003 Oct;27(10):1152-66. View Abstract

12. U.S. Food and Drug Administration (FDA). www.fda.gov.