Scientists discover why the brain may lead to weight loss stalling


A new study conducted at the University of Cambridge has found that a group of neurons in the brain coordinates energy intake and energy output when dieting.

The findings, which revisit the energy-balance equation, have implications for predicting the outcome of different weight loss interventions in obesity and type 2 diabetes.

Researchers knew that when we eat less, the body tends to compensate and burn fewer calories. But, how energy expenditure (calories out) is adjusted when calories are restricted remained unclear.

These new findings suggest that the brain regulates this caloric thermostat. In the journal eLife, researchers explain that, in mice, the brain responds to a calorie deficit by increasing hunger and decreasing the number of calories burned.

In other words, it turns the body into saving mode, which leads to barely measurable rises in energy expenditure and no increase in loss of body fat over time.

The group of neurons responsible for this phenomenon are known as the agouti-related neuropeptide (AGRP) neurons. They are located in the hypothalamus and represent about 10,000 neuron cells that are activated by fasting and refeeding.

When activated, the AGRP neurons act to spare energy, limiting the number of calories burned and hence the weight loss. They do that by decreasing thermogenesis (fat burning) in brown adipose tissue (BAT).

In the study’s experiment, mice that were food-restricted and genetically modified to have altered function of those neurons burned fewer calories.

The other interesting finding is that the AGRP neurons can detect how much energy is available through nutrient-sensing pathways, like mTORC1, and then control how many calories are burned accordingly.

The number of calories consumed is therefore important, but so is the type of diet as researchers found that exposing mice to a high-fat diet for several days inhibited their AGRP neurons, causing them to burn calories at a faster rate.

This is in line with the metabolic advantage purportedly associated with a low-carb, high-fat diet which is that it allows fat burning leading to weight loss.

Overall, the findings suggest that during caloric restriction, calories out may initially rise but eventually fall due to the action of the AGRP neurons which limits the rate of fat loss.


Pineapple Benefits For Weight Loss


I’m not here to tell you that pineapple will magically melt fat, because it won’t. But what it will do is fuel your body with the necessary nutrients that can help you achieve your weight loss goal. Furthermore, pineapple has a unique inflammation-fighting enzyme.  And, inflammation and weight gain are closely connected.

How does pineapple burn fat?

Pineapple is juicy, sweet and delicious. It’s often misrepresented as a fruit that can burn fat, most likely because of its main enzyme, bromelain. Bromelain can help reduce inflammation in the body — but more on that later. However, even if pineapple can’t physically burn fat, it does have nutrients that can certainly help you reduce fat. So, don’t give up on pineapple just yet.

High vitamin C content turns fat to fuel


Many benefits of pineapple are due to its high concentration of vitamin C. Vitamin C is a water-soluble vitamin, which means your body doesn’t store it. Therefore, you need to get enough from vitamin C-rich foods like pineapples. Vitamin C plays an important role in maintaining the health of the body’s connective tissue as well as acting as an antioxidant. The RDA for vitamin C is 90 milligrams a day for men and 75 milligrams a day for women. The daily value (DV) is 60 milligrams. DVs are based on a 2,000-calorie diet for healthy adults. Pineapple has a whopping 79 milligrams of vitamin C per cup. That 131 percent of the daily value.

Too little vitamin C in the blood stream leads to increased body fat and waist measurements. A 2006study from Arizona State University reported that the amount of vitamin C in the blood stream is directly related to fat oxidation (the body’s ability to use fat as fuel) during both exercise and at rest.

At the beginning of the study, participants with the lowest concentrations of vitamin C in their blood had the highest body fat mass. They could not oxidize fat as well as those participants who were less obese. But, as the study progressed, those same participants who consumed a steady amount of vitamin C increased blood vitamin C concentrations by 30 percent. The participants who only consumed 67 percent of the recommended daily allowance from food saw a decline in vitamin C blood concentration. So, their ability to oxidize fat decreased.

Since pineapple is such an excellent source of vitamin C, just one cup a day could aid your body’s ability to turn your fat into fuel.

Is pineapple good to eat on a diet?

Low in calories, nutrient-rich and a good source of fiber makes this tropical treat a great addition to any diet. Pineapple consists of 86 percent water and 13 percent carbs, and no fat or protein. At only 83 calories per cup, pineapple is ideal as a low-calorie snack or dessert.

It’s also an excellent source of manganese, a mineral needed to metabolize carbohydrates and fat, which is important for energy production. Low manganese levels are linked with osteoporosis, diabetes, arthritis, PMS and epilepsy, according to the University of Maryland. But manganese deficiency is rare in the United States. One cup of pineapple supplies you with about 2 milligrams of manganese. Adult males need about 2.3 milligrams daily and adult females need 1.8 milligrams.

Pineapple won’t affect blood sugar

The glycemic index (GI) is a measurement for carbohydrate-containing foods and how they affect blood glucose levels. Low GI diets are linked with decreased risk of certain conditions like cardiovascular disease, type 2 diabetes, metabolic syndrome and stroke. Carbohydrates with a low GI value of 55 or less are more slowly digested, absorbed and metabolized. In turn, they cause a lower and slower rise in blood glucose and, therefore, insulin levels.

The glycemic index value of pineapples ranges from 45 to 66. That places them at a low to medium range, according to the University of Sydney, which means that pineapples should not have any major effects on blood sugar levels.

It is a good source of insoluble fiber

One cup of pineapple contains two grams of fiber. Almost all — 99 percent of it — is insoluble. Insoluble fiber is the type of fiber that most people think of as “roughage.” It’s the hardy fiber found in whole grains, nuts, veggies and fruits that don’t dissolve in water. In fact, insoluble fiber isn’t broken down by the gut and absorbed into the bloodstream. Instead, it adds bulk to waste in the digestive system. That helps keep you regular and prevents constipation. Your total dietary fiber intake should be around 25 to 30 grams a day from food — not supplements.

Fiber is so important for dieting because it requires more chewing and takes longer to digest. This helps your body recognize that it is full and prevents you from continuing to eat. Diets rich in fiber are linked to decreased risk of cardiovascular disease. Insoluble fibers have also been linked to reduced risk of type 2 diabetes, according to a German study. And another study by the American Dietetic Association found the insoluble fiber leads to lower body weight.

Can pineapple juice help you lose weight?

Pineapple juice is packed with vitamins and minerals, but it can’t magically help you lose weight. That said, it offers a significant amount of vitamin C, which aids in weight loss. It may also help reduce your risk of constipation and improve overall digestion. But the real benefit to pineapple juice is bromelain.

The bromelain connection

Bromelain is a mixture of enzymes found in pineapples that digest protein. Bromelain can be used to treat several conditions. But it is particularly effective in reducing inflammation. Although inflammation is part of the body’s natural defense system, too much wreaks havoc on your body. Incidentally, eating the fiber-rich core of a juicy, ripe pineapple is the best way to consume natural sources of bromelain. The riper the fruit is, the softer the core will be.

A great way to get your bromelain fix is by juicing the core of the pineapple or simply throwing it into a smoothie. Drinking fresh pineapple juice has been shown to be a powerful remedy against inflammatory diseases. A Duke University Medical study found that supplementing your diet with fresh pineapple juice actually decreases inflammation.

And inflammation is the link between obesity and metabolic syndrome, suggests a study in the Journal of Nutrition and Metabolism.

Get your energy from pineapple

Pineapple is a good source of thiamin, which is a B vitamin that’s essential to energy production. And, anyone who’s ever been on a diet understands the importance energy plays. Let’s face it, when your energy is low, that’s when you’re most likely to grab a box of high-sugar, high-fat cookies.

Pineapple not only fills you up with few calories, but it will also provide you with a healthy source of fuel — that combats inflammation! Pineapple may not a miracle fat-burning fruit that some claim, but there are definite reasons why you should include it in your diet.

— Katherine Marko

Is the ‘8-Hour Diet’ the key to weight loss?

What time did you eat your dinner last night? Chances are it was at 7 or even 8 p.m. And what about your breakfast? If your days are long, it is likely you grabbed a coffee or a piece of toast pretty early in the day. As the scientific evidence linking intermittent fasting to hormonal control and weight loss has grown so, too, has interest in prolonged periods of time within each day that we actually do not eat. Forget calorie counting or limiting your carbs — weight control may be as simple as eating across fewer hours each day.

The 8-Hour Diet proposes that limiting your food intake to just eight hours of the day is an easy diet technique that supports weight control. This way, all calories and meals need to be consumed within just eight hours of the day — for example, brunch at 10 a..m, lunch at 1 or 2 p.m. and your final meal of the day by 6 p.m. The amount of calories or even fat consumed is not important — rather, it is argued that our long days, in which food may be consumed across as many as 16 hours each day, is one of the key reasons so many of us are struggling with our weight.


Indeed, there are some physiological aspects of this argument that make sense. Prolonged periods of feeding, in which food is not only consumed relatively frequently, every few hours and across many hours of the day means that more insulin (the hormone that controls blood glucose levels) is released in an attempt to keep blood glucose levels stable. High levels of insulin over time promote inflammation and fat storage in the body. In addition, hunger is less likely to be experienced, as we never really let ourselves get really hungry and fat is more likely to be stored in the liver.

Studies on animals support this approach when it comes to weight loss and hormonal control. In some preliminary studies, rats given free access to high-fat foods but only for relatively short periods of time weighed less, and had no issues with their cholesterol levels, blood glucose levels or inflammation in the liver. On the other hand, rats given free access to food across 24-hour periods gained weight, developed high cholesterol and high blood glucose as well as impaired motor control. Researchers concluded that constant feeding results in the body going into storage mode — gaining weight and placing stress on the liver, which in turn results in increased blood glucose levels. On the other hand, when we stop eating for a number of hours, the liver stops releasing glucose into the bloodstream and instead uses it to repair the body’s cells, which in turn reduced inflammation. In addition, cholesterol is more likely to be broken down rather than stored.


So what does this mean for us? There is more evidence building to show there is a number of health benefits associated with not eating for a number of hours, from both a hormonal and weight perspective. In real life, though, this is easier said than done with long hours and shift work resulting in meals and snacks being consumed at all times of the day and night. The environment in which we live also encourages food consumption constantly, regardless of hunger or meal time.

While the exact period of time in which metabolic benefits are experienced from not eating is unknown, it appears that leaving at least 12 hours per day without food is beneficial, and at an extreme 16 hours each day. In real life terms, this means a later start to the day food-wise, and consuming your final meal by 8 p.m. at the latest. Another option if your day starts early is to eat breakfast as normal, eat your main meal at lunchtime and then have a light snack by 6pm. This way you still have 12-14 hours without food each day but are still eating enough calories so you do not experience extreme hunger throughout the evening.

The biggest issue with diets that limit calories in some way is that extreme hunger is then experienced which makes compliance challenging. The key thing with fasting is that for it to work you need to not eat anything, whereas in real life little extras slip in which negate the benefits. As such, for the 8 Hour Diet to be effective, you will need to consume a substantial meal at some point during the day so that your hunger does not get the better of you.

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