Unintentional weight loss may result from loss of body fats, loss of body fluids, muscle atrophy, or a combination of these.[25][26] It is generally regarded as a medical problem when at least 10% of a person's body weight has been lost in six months[25][27] or 5% in the last month.[28] Another criterion used for assessing weight that is too low is the body mass index (BMI).[29] However, even lesser amounts of weight loss can be a cause for serious concern in a frail elderly person.[30]
Long-term use of the ketogenic diet in children increases the risk of slowed or stunted growth, bone fractures, and kidney stones.[18] The diet reduces levels of insulin-like growth factor 1, which is important for childhood growth. Like many anticonvulsant drugs, the ketogenic diet has an adverse effect on bone health. Many factors may be involved such as acidosis and suppressed growth hormone.[38] About one in 20 children on the ketogenic diet develop kidney stones (compared with one in several thousand for the general population). A class of anticonvulsants known as carbonic anhydrase inhibitors (topiramate, zonisamide) are known to increase the risk of kidney stones, but the combination of these anticonvulsants and the ketogenic diet does not appear to elevate the risk above that of the diet alone.[39] The stones are treatable and do not justify discontinuation of the diet.[39] Johns Hopkins Hospital now gives oral potassium citrate supplements to all ketogenic diet patients, resulting in one-seventh of the incidence of kidney stones.[40] However, this empiric usage has not been tested in a prospective controlled trial.[9] Kidney stone formation (nephrolithiasis) is associated with the diet for four reasons:[39]
But beyond that, experts aren't convinced that the keto diet has any other scientifically-proven health benefits. In fact, it may have some distinct downsides. If you follow the keto diet incorrectly, for example (like by eating lots of saturated fats, versus healthy unsaturated fats), you're at risk of raising your cholesterol levels. “The best strategy to keep your heart healthy is to get as much fat as possible from unsaturated sources such as olive, avocado and canola oils, nuts, seeds, avocados, and olives," says Ansel.
For patients who benefit, half achieve a seizure reduction within five days (if the diet starts with an initial fast of one to two days), three-quarters achieve a reduction within two weeks, and 90% achieve a reduction within 23 days. If the diet does not begin with a fast, the time for half of the patients to achieve an improvement is longer (two weeks), but the long-term seizure reduction rates are unaffected.[44] Parents are encouraged to persist with the diet for at least three months before any final consideration is made regarding efficacy.[9]
The remaining calories in the keto diet come from protein — about 1 gram (g) per kilogram of body weight, so a 140-pound woman would need about 64 g of protein total. As for carbs: “Every body is different, but most people maintain ketosis with between 20 and 50 g of net carbs per day,” says Mattinson. Total carbohydrates minus fiber equals net carbs, she explains.
The brain is composed of a network of neurons that transmit signals by propagating nerve impulses. The propagation of this impulse from one neuron to another is typically controlled by neurotransmitters, though there are also electrical pathways between some neurons. Neurotransmitters can inhibit impulse firing (primarily done by γ-aminobutyric acid, or GABA) or they can excite the neuron into firing (primarily done by glutamate). A neuron that releases inhibitory neurotransmitters from its terminals is called an inhibitory neuron, while one that releases excitatory neurotransmitters is an excitatory neuron. When the normal balance between inhibition and excitation is significantly disrupted in all or part of the brain, a seizure can occur. The GABA system is an important target for anticonvulsant drugs, since seizures may be discouraged by increasing GABA synthesis, decreasing its breakdown, or enhancing its effect on neurons.[7]

There is a substantial market for products which claim to make weight loss easier, quicker, cheaper, more reliable, or less painful. These include books, DVDs, CDs, cremes, lotions, pills, rings and earrings, body wraps, body belts and other materials, fitness centers, clinics, personal coaches, weight loss groups, and food products and supplements.[22]

As chronic obstructive pulmonary disease (COPD) advances, about 35% of patients experience severe weight loss called pulmonary cachexia, including diminished muscle mass.[31] Around 25% experience moderate to severe weight loss, and most others have some weight loss.[31] Greater weight loss is associated with poorer prognosis.[31] Theories about contributing factors include appetite loss related to reduced activity, additional energy required for breathing, and the difficulty of eating with dyspnea (labored breathing).[31]


A computer program such as KetoCalculator may be used to help generate recipes.[47] The meals often have four components: heavy whipping cream, a protein-rich food (typically meat), a fruit or vegetable and a fat such as butter, vegetable oil, or mayonnaise. Only low-carbohydrate fruits and vegetables are allowed, which excludes bananas, potatoes, peas, and corn. Suitable fruits are divided into two groups based on the amount of carbohydrate they contain, and vegetables are similarly divided into two groups. Foods within each of these four groups may be freely substituted to allow for variation without needing to recalculate portion sizes. For example, cooked broccoli, Brussels sprouts, cauliflower, and green beans are all equivalent. Fresh, canned, or frozen foods are equivalent, but raw and cooked vegetables differ, and processed foods are an additional complication. Parents are required to be precise when measuring food quantities on an electronic scale accurate to 1 g. The child must eat the whole meal and cannot have extra portions; any snacks must be incorporated into the meal plan. A small amount of MCT oil may be used to help with constipation or to increase ketosis.[37]
There is a substantial market for products which claim to make weight loss easier, quicker, cheaper, more reliable, or less painful. These include books, DVDs, CDs, cremes, lotions, pills, rings and earrings, body wraps, body belts and other materials, fitness centers, clinics, personal coaches, weight loss groups, and food products and supplements.[22]
This principle involves eating low-energy-dense foods and can help you lose weight by feeling full on fewer calories. Healthy choices in each of the other food groups in moderate amounts make up the rest of the pyramid — including whole-grain carbohydrates, lean sources of protein such as legumes, fish and low-fat dairy, and heart-healthy unsaturated fats.
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