We’ve all seen the goods; fat loss/weight loss/fat burning proteins, containing ingredients capable of helping you “burn fat”, “lose weight” and even helping to “build muscle” in the latter case, all the while you are living your everyday life. But how effective are these supplements and the ingredients they contain in meeting their claims? For the rest of this article, we will break down systematically the most common ingredients and nutrients contained in common fat loss proteins and fat loss products to find out the efficacy and safety of these ingredients.

How Weight Loss Proteins Work

Most of the ingredients contained in fat loss products including fat loss proteins generally work in 1 of 4 ways:

  • Affecting carbohydrate metabolism – Commonly known as “carb blockers”
  • Affecting fat metabolism – Commonly known as “fat metabolisers”
  • Affecting metabolic rate – Commonly known as “thermogenics”
  • Acts as an appetite suppressant

Some of the ingredients mentioned here are even able to act in more than one way. As this article is quite long and detailed, for ease of reading this article will be split into 3 parts; the first part will look at carb blockers, the second on thermogenics, while the third article will look at fat metabolisers.

Blocking Carbohydrates

Many fat loss proteins and other fat loss products are said to be able to ‘block carbs’. This involves either interference in carbohydrate digestion or through use of nutrients which are supposedly able to shift carbohydrates into glycogen storage rather than fat storage. By interfering with digestion, the amount of energy coming from carbs is reduced resulting in decreased energy consumption overall. Shifting carbohydrates away from fat storage also has the potential to reduce fat mass and body fat percentage. Commonly used ingredients include:

Phaseolus Vulgaris

Phaseolus vulgaris is the latin name for the common bean, including kidney, cannellini and borlotti among others. An active ingredient in cannellini beans and other white beans known as phaseolamin is a known potent inhibitor of alpha amylase, an enzyme produced by us to digest starches found in carbohydrates. Theoretically then, consumption of phaseolamin has the potential to inhibit or at the very least slow down the digestion and thus absorption of complex carbohydrates resulting in a lowered energy and caloric intake. Indeed this has been shown to be the case. Several studies have been performed since the development of the first ‘starch blocker’ utilising phaseolamin in the late 1990s. Barrett and Udani (2011)1 reviewed the evidence surrounding the use of phaseolamin and its effect on weight loss and found that weight loss was significantly higher in those that consumed phaseolamin than those who didn’t, even when overall energy intake was controlled. Throughout the 10 studies reviewed, weight loss ranged from 45-700g/week with intake of a phaseolamin supplement between 500-3000mg. Furthermore, consumption of phaseolamin was shown in some studies to positively impact blood glucose/insulin response, triglycerides as well as waist circumference. Even studies without statistical significance showed that participants who consumed phaseolamin had higher total weight loss than those who didn’t consume phaseolamin. Interestingly, white beans contain a higher level of lectin, a toxin which may cause gastrointestinal issues as well as leptin resistance. Leptin is a chemical messenger that lets us know when we are full. Leptin resistance can therefore lead to a delayed fullness response. However, as long as you cook your beans properly then this will not be an issue. Neither is consuming the active ingredient phaseolamin by itself.

Hydroxycitric Acid & Fat Loss

Hydroxycitric acid (HCA) is the primary acid found in plant species belonging to the group Garcinia. This acid is often found in the rinds of fruits coming from this plant species. It has been shown that HCA has the potential to inhibit citrate lyase and as a result, lipogenesis2. That is, HCA has the potential to disrupt the conversion of carbohydrates to fats. There is some evidence in animal studies3 that HCA is able to affect fat metabolism as well as a long term suppression of dietary intake, however, these results have not been able to translate over to the human population in the majority of the studies conducted with hydroxycitric acid. A couple of studies has shown that consumption levels of between 1.5-3g/day of HCA is unable to significantly alter weight loss, fat loss or appetite4,5,6. On the other hand however, a Preuss et al (2004)7 was able to show that a novel supplement under the name ‘Super CitriMax’ was able to significantly and positively affected body weight, BMI, food intake, cholesterol levels including their fractions (HDL, LDL and triglycerides) and leptin levels. The supplement in this study provided approximately 2.8g of HCA. Studies have shown that HCA appears to be safe at doses under 3mg/day, as you would see in many fat loss protein powders.

Carb Blockers vs Carb Intake

It is sometimes perplexing why carbohydrates are seen in such a negative light when it comes to fat loss. Correct and portioned consumption of complex carbohydrates is important in maintaining a healthy/balanced diet. Complex carbohydrates contain a wide variety of important and health benefitting nutrients, which may become insufficient and even absent in low carbohydrate diets. Furthermore, carbohydrates are required to restore glycogen levels in your muscles of which are a primary fuel source. Low levels of glycogen in your muscles can be a detriment to your workouts as a result of quicker fatigue rates and loss of strength. While low carbohydrate, high protein diets have been shown to be effective in fat loss8, if you were considering reduction of carbs as a main criteria in your fat loss approach, it is advisable that you do no go overboard, and include some complex carbohydrates and plenty of fruits and vegetables, which themselves contain nutrients which may aid weight/fat loss. Fat loss proteins and products containing phaseolamin can potentially be quite effective in helping to promote weight/fat loss. Unfortunately, the amount of phaseolamin in products is sometimes absent in the packaging. From the evidence above, try to make sure that your protein or fat loss supplement is able to provide you with at least 500mg of phaseolamin. Please call the parent companies if unsure. If you were buying fat loss proteins on the basis of their HCA content, evidence suggests that it is still too early to tell whether it can significantly affect weight/fat loss, although it does have worthy prospects. Keep in mind though that if your fat loss protein or product contains HCA, that you do not over consume it keeping HCA consumption under 3mg/day.

To be continued…Stay tuned for part 2 of this series on fat loss proteins and products which will examine in more detail ingredients in fat loss proteins stated as thermogenics.

1 Barrett ML, Udani JK. ‘A proprietary alpha-amylase inhibitor from white bean (Phaseolus vulgaris): a review of clinical studies on weight loss and glycemic control.’ Nutr J. 2011 Mar 17;10:24.
2
Jena BS, Jayaprakasha GK, Singh RP, Sakariah KK. ‘Chemistry and biochemistry of (-)-hydroxycitric acid from Garcinia.’ J Agric Food Chem. 2002 Jan 2;50(1):10-22.
3
Ishihara K, Oyaizu S, Onuki K, Lim K, Fushiki T. ‘Chronic (-)-hydroxycitrate administration spares carbohydrate utilization and promotes lipid oxidation during exercise in mice.’ J Nutr. 2000 Dec;130(12):2990-5.
4
Heymsfield SB, Allison DB, Vasselli JR, Pietrobelli A, Greenfield D, Nunez C. ‘Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial.’ JAMA. 1998 Nov 11;280(18):1596-600.
5
Mattes RD, Bormann L. ‘Effects of (-)-hydroxycitric acid on appetitive variables.’ Physiol Behav. 2000 Oct 1-15;71(1-2):87-94.
6
Kriketos AD, Thompson HR, Greene H, Hill JO. ‘(-)-Hydroxycitric acid does not affect energy expenditure and substrate oxidation in adult males in a post-absorptive state.’ Int J Obes Relat Metab Disord. 1999 Aug;23(8):867-73.
7
Preuss HG, Rao CV, Garis R, Bramble JD, Ohia SE, Bagchi M, Bagchi D. ‘An overview of the safety and efficacy of a novel, natural(-)-hydroxycitric acid extract (HCA-SX) for weight management.’ J Med. 2004;35(1-6):33-48.
8
Nordmann AJ, Nordmann A, Briel M, Keller U, Yancy WS Jr, Brehm BJ, Bucher HC. ‘Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials.’ Arch Intern Med. 2006 Feb 13;166(3):285-93.

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