Yogurt, kefir, milk, cheese and other dairy foods have been a staple in the human diet for centuries. Nowadays, they have a bad rep because of their lactose content, among other issues. Any vegan will tell you that cow's milk is meant only for baby cows.
Yet, health experts worldwide recommend the consumption of milk and dairy. These foods are high in calcium and protein, offering a lot of nutrition per serving. In fact, certain dairy products, such as kefir and yogurt, can make weight loss easier and restore the gut flora.
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The bacteria living in your gut affect your weight and metabolism. Kefir and other fermented foods balance the gut flora and may aid in fat loss. Additionally, they are low in calories and rich in protein, calcium and other beneficial compounds that support metabolic health.
Kefir — Healthy or Hype?
This tangy yogurt drink is loaded with "good" bacteria and yeast that form during the fermentation process. According to a November 2017 review published in Medical Oncology, kefir protects against pathogens, fights inflammation and wards off allergies. On top of that, it's rich in peptides and other bioactive compounds that may induce cancer cell death.
Kefir can be made with goat, cow or sheep milk. Some varieties are fermented with water or plant-based milk substitutes, such as rice, soy or coconut milk.
The beneficial bacteria and yeasts occur naturally in kefir grains, a by-product of milk straining. These include Lactobacillus species, such as L. acidophilus, L. helveticus and L.brevis, and yeasts like Candida kefyr and Issatchenkia orientalis, as reported in a review published in the Brazilian Journal of Microbiology in October 2013.
The same source states that kefir displays antimicrobial, anti-inflammatory, anticarcinogenic and immune-boosting properties. Some studies suggest that it may also lower cholesterol and triglyceride levels, but more research is needed to confirm these findings. In clinical trials, kefir consumption has been shown to protect and restore the intestinal mucosa, reduce enterobacteria and other pathogens, inhibit tumor growth and improve immune function.
According to the Brazilian Journal of Microbiology review, kefir is lower in lactose than milk and can be safely consumed by lactose-intolerant adults. Beta-galactosidase, a naturally occurring enzyme in this fermented drink, reduces its lactose content.
Kefir Nutritional Value
Low in calories and fat, this fermented milk beverage fits into most diets. Several varieties exist and each has a different nutritional value. Plain, low-fat kefir, for example, has just 100 calories per serving (one cup). You'll also get:
- 9.2 grams of protein
- 2.3 grams of fat
- 10.9 grams of carbs
- 24.5 percent of the DV (daily value) of calcium
- 10 percent of the DV of zinc
- 9 percent of the DV of potassium
- 7 percent of the DV of magnesium
- 46 percent of the DV of vitamin A
- 12 percent of the DV of vitamin D
- 29 percent of the DV of vitamin B12
Kefir also contains small doses of riboflavin, thiamin, folate and other B-complex vitamins. Low-fat Greek yogurt, by comparison, has 183 calories, 24.9 grams of protein, 4.8 grams of fats and 9.9 grams of carbs, including 8.9 grams of sugars per serving (one cup). It is higher in calcium, zinc, potassium, vitamin A and vitamin B12, but it also packs more calories and carbs.
Beware that some manufacturers add sugar and additives to kefir. In general, flavored varieties, such as strawberry kefir, are the highest in sugar.
If you have a sweet tooth, mix plain kefir with fresh or dried fruits, nuts, seeds, vanilla and other healthful ingredients. You can even add a scoop of protein powder for extra flavor and nutrition.
This fermented beverage isn't particularly high in calcium or protein. What makes it stand out is its probiotic content.
According to an October 2015 review published in Frontiers in Microbiology, kefir boasts more than 23 yeast species along with several bacteria species, including Gluconobacter frateurii, Lactococcus lactis and Lactobacillus paracasei. Its microbial composition depends on its origin, among other factors.
The beneficial bacteria in kefir have been shown to improve blood lipids, inhibit cholesterol absorption and inhibit or kill pathogens. This drink also contains kefiran, a natural sugar produced by Lactobacillus kefiranofaciens. As the review authors note, kefiran exhibits antimicrobial, anti-cancer, antioxidant and anti-inflammatory properties. This natural compound may lower blood pressure, suppress tumor growth and modulate the intestinal immune system.
Kefir and Weight Loss
Kefir can help you slim down in more than one way. First of all, it's low in calories and makes a perfect treat between meals. You can cut calories just by replacing your morning latte with this fermented drink.
The good bacteria in kefir help maintain a balanced internal ecosystem and support gut health. As mentioned earlier, these microorganisms fight pathogens while increasing the number of beneficial bacteria in your digestive tract. What you may not know is that your gut flora has a direct impact on body weight. In fact, microbial changes in the gut may contribute to weight gain and obesity.
A December 2014 review featured in the International Journal of Environmental Research and Public Health examined the relationship between gut microbiota and obesity. Researchers suggest that probiotics and prebiotics (food ingredients that beneficial gut bacteria can feed off) influence appetite, metabolism, body composition and weight. Furthermore, microbial imbalances can affect the levels of hunger hormone ghrelin and promote fat storage.
Read more: 13 Surprising and Beneficial Probiotic Foods
As reported in the above review, alterations in the gut flora may increase or inhibit the production of ghrelin, peptide tyrosine tyrosine (PYY) and other hormones that influence appetite. If you're feeling hungry all the time, your gut might be out of whack. That's where fermented foods and beverages can help.
For example, L. acidophilus, one of the most abundant bacterial species in kefir and other fermented dairy foods, increases satiety to a greater extent than non-fermented dairy products. In one study reported in the above review, women who consumed probiotics and prebiotics for 24 weeks lost significantly more weight compared to the placebo group. Other studies cited in the same review found that probiotics may help reduce abdominal fat, total fat mass and body mass index.
Kefir Promotes Metabolic Health
The anti-obesity effects of kefir are due to its unique composition of beneficial bacteria. According to a review published in Evidence-Based Complementary and Alternative Medicine in April 2019, probiotics may reduce weight gain, aid in obesity treatment and improve metabolic health.
After analyzing 10 studies conducted on 641 adults, researchers found that subjects consuming probiotics experienced a greater reduction in body weight than those who didn't.
Other studies have shown that probiotics may help decrease waist circumference and fat mass, improve cholesterol levels and lower blood sugar levels. As the scientists point out, these microorganisms may reduce fat storage and inflammation while improving insulin response, leading to better metabolic health.
Another research paper, which appeared in the November 2013 edition of the journal Nutrients, shows a strong link between dairy foods and weight loss. This time, the researchers focused on protein, calcium, potassium and other nutrients in dairy products. In clinical trials, these foods have been found to increase lean mass, reduce adiposity and facilitate weight loss when consumed as part of a calorie-controlled diet.
Protein, for example, increases satiety and can make weight loss easier, as the review authors note. Calcium, another key nutrient in dairy foods, stimulates fat breakdown and reduces fat accumulation. Some dairy products are rich in conjugated linoleic acid, a fatty acid that improves the body's ability to burn fat for fuel.
Read more: The 6 Best Yogurts and 4 to Avoid
These studies confirm that dairy products, including kefir, can help you shed stubborn fat and keep it off. The key is to consume them as part of a healthy diet.
According to the USDA, adults should consume three cups of dairy foods daily. To lose weight, start your day with a cup of kefir, enjoy another one between meals and drink a third cup before bedtime or whenever hunger strikes.
- Medical Oncology: "Kefir: A Powerful Probiotics With Anticancer Properties"
- Brazilian Journal of Microbiology: "Microbiological, Technological and Therapeutic Properties of Kefir: A Natural Probiotic Beverage"
- USDA: "Nutrition Facts for Kefir Low-Fat Plain Lifeway"
- USDA: "Nutrition Facts for Low-Fat Greek Yogurt"
- Frontiers in Microbiology: "Milk Kefir: Composition, Microbial Cultures, Biological Activities, and Related Products"
- NCBI: Future Microbiology: "The Relationship Between Gut Microbiota and Weight Gain in Humans"
- MDPI: International Journal of Environmental Research and Public Health: "Childhood Obesity: A Role for Gut Microbiota?"
- Evidence-Based Complementary and Alternative Medicine: "The Potential Role of Probiotics in Controlling Overweight/Obesity and Associated Metabolic Parameters in Adults: A Systematic Review and Meta-Analysis"
- MDPI: Nutrients: "Dairy Foods and Dairy Protein Consumption Is Inversely Related to Markers of Adiposity in Obese Men and Women"
- USDA: "Dairy"
- Journal of Dairy Science: "Short Communication: Evaluation of the Microbiota of Kefir Samples Using Metagenetic Analysis Targeting the 16S and 26S Ribosomal DNA Fragments"