Many people are on low-carbohydrate diets in order to lose weight, control or stave off diabetes, improve their cholesterol counts and blood pressure and avoid heart attacks, strokes and hemorrhages. It can be more difficult to maintain a low-carb diet while travelling, especially if you need to eat a lot of food in restaurants or as a guest in the private homes of people who may not make allowances for your diet, but it is by no means unworkable. This article is designed to give you some ideas to help you manage your diet while you are on the road, have fun and be successful in meeting your goals.

Low-carbohydrate diets or carbohydrate-restricted diets (CRDs) are diets that restrict carbohydrate consumption. Foods high in carbohydrates (e.g., sugar, bread, pasta) are limited or replaced with foods containing a higher percentage of fats and moderate protein (e.g., meat, poultry, fish, shellfish, eggs, cheese, nuts, and seeds) and other foods low in carbohydrates (e.g., most salad vegetables such as spinach, kale, chard and collards), although other vegetables and fruits (especially berries) are often allowed.

There is a lack of standardization of how much carbohydrate low-carbohydrate diets must have, and this has complicated research. One definition, from the American Academy of Family Physicians, specifies low-carbohydrate diets as having less than 20% carbohydrate content.

Low-carbohydrate diets are associated with increased mortality, and they can miss out on the health benefits afforded by high-quality carbohydrate such as is found in legumes including grain legumes or pulses, and fruit and vegetables. Disadvantages of the diet might include halitosis, headache and constipation, and in general the potential adverse effects of the diet are under-researched, particularly for more serious possible risks such as for bone health and cancer incidence.

Carbohydrate-restricted diets can be as effective, or marginally more effective, than low-fat diets in helping achieve weight loss in the short term. In the long term, effective weight maintenance depends on calorie restriction, not the ratio of macronutrients in a diet. The hypothesis proposed by diet advocates that carbohydrate causes undue fat accumulation via the medium of insulin, and that low-carbohydrate diets have a “metabolic advantage”, has been falsified by experiment.

It is not clear how low-carbohydrate dieting affects cardiovascular health; any benefit from HDL cholesterol might be offset by raised LDL cholesterol, which risks causing clogged arteries in the long term.

Carbohydrate-restricted diets are no more effective than a conventional healthy diet in preventing the onset of type 2 diabetes, but for people with type 2 diabetes they are a viable option for losing weight or helping with glycemic control. There is little evidence that low-carbohydrate dieting is helpful in managing type 1 diabetes. The American Diabetes Association recommends that people with diabetes should adopt a generally healthy diet, rather than a diet focused on carbohydrate or other macronutrients.

An extreme form of low-carbohydrate diet – the ketogenic diet – is established as a medical diet for treating epilepsy. Through celebrity endorsement it has become a popular weight-loss fad diet, but there is no evidence of any distinctive benefit for this purpose, and it may have a number of initial side effects. The British Dietetic Association named it one of the “top 5 worst celeb diets to avoid in 2018”.

Definition and classification

Macronutrient ratios
The macronutrient ratios of low-carbohydrate diets are not standardized. As of 2018 the conflicting definitions of “low-carbohydrate” diets have complicated research into the subject.

The American Academy of Family Physicians defines low-carbohydrate diets as diets that restrict carbohydrate intake to 20 to 60 grams per day, typically less than 20% of caloric intake. A 2016 review of low-carbohydrate diets classified diets with 50g of carbohydrate per day (less than 10% of total calories) as “very low” and diets with 40% of calories from carbohydrates as “mild” low-carbohydrate diets. In a 2015 review Richard D. Feinman and colleagues proposed that a very low carbohydrate diet had less that 10% caloric intake from carbohydrate, a low carbohydrate diet less than 26%, a medium carbohydrate diet less than 45%, and a high carbohydrate diet more than 45%.

Both high- and low-carbohydrate (less than 40% of calories from carbohydrate) diets are associated with increased mortality. The optimal proportion of carbohydrate in a diet for health is thought to be 50-55%.

Foodstuffs
There is evidence that the quality, rather than the quantity, of carbohydrate in a diet is important for health, and that high-fiber slow-digesting carbohydrate-rich foods are healthful while highly-refined and sugary foods are less so. People choosing diet for health conditions should have their diet tailored to their individual requirements. For people with metabolic conditions, in general a diet with approximately 40-50% high-quality carbohydrate is compatible with what is scientifically established to be a healthy diet.

Some fruits may contain relatively high concentrations of sugar, most are largely water and not particularly calorie-dense. Thus, in absolute terms, even sweet fruits and berries do not represent a significant source of carbohydrates in their natural form, and also typically contain a good deal of fiber which attenuates the absorption of sugar in the gut.

Most vegetables are low- or moderate-carbohydrate foods (in some low-carbohydrate diets, fiber is excluded because it is not a nutritive carbohydrate). Some vegetables, such as potatoes, carrots, maize (corn) and rice are high in starch. Most low-carbohydrate diet plans accommodate vegetables such as broccoli, spinach, kale, lettuce, cucumbers, cauliflower, peppers and most green-leafy vegetables.

In 2004, the Canadian government ruled that foods sold in Canada could not be marketed with reduced or eliminated carbohydrate content as a selling point, because reduced carbohydrate content was not determined to be a health benefit. The government ruled that existing “low carb” and “no carb” packaging would have to be phased out by 2006.

Adoption and advocacy
The National Academy of Medicine recommends a minimum intake of 130 g of carbohydrate per day. The FAO and WHO similarly recommend that the majority of dietary energy come from carbohydrates. Low-carbohydrate diets are not an option recommended in the 2015-2020 edition of Dietary Guidelines for Americans, which instead recommends a low fat diet.

Carbohydrate has been wrongly accused of being a uniquely “fattening” macronutrient, misleading many dieters into compromising the nutritiousness of their diet by eliminating carbohydrate-rich food. Low-carbohydrate diet proponents emphasize research saying that low-carbohydrate diets can initially cause slightly greater weight loss than a balanced diet, but any such advantage does not persist. In the long-term successful weight maintenance is determined by calorie intake, and not by macronutrient ratios.

The public has become confused by the way in which some diets, such as the Zone diet and the South Beach diet are promoted as “low-carbohydrate” when in fact they would more properly be termed “medium” carbohydrate diets.

Carbohydrate-insulin hypothesis
Low-carbohydrate diet advocates including Gary Taubes and David Ludwig have proposed a “carbohydrate-insulin hypothesis” in which carbohydrate is said to be uniquely fattening because it raises insulin levels and so causes fat to accumulate unduly. The hypothesis appears to run counter to known human biology whereby there is no good evidence of any such association between the actions of insulin and fat accumulation and obesity. The hypothesis predicted that low-carbohydrate dieting would offer a “metabolic advantage” of increased energy expenditure equivalent to 400-600 kcal/day, in accord with the promise of the Atkin’s diet: a “high calorie way to stay thin forever”.

With funding from the Laura and John Arnold Foundation, in 2012 Taubes co-founded the Nutrition Science Initiative (NuSI), with the aim of raising over $200 million to undertake a “Manhattan Project for nutrition” and validate the hypothesis. Intermediate results, published in the American Journal of Clinical Nutrition did not provide convincing evidence of any advantage to a low-carbohydrate diet as compared to diets of other composition – ultimately a very low-calorie, ketogenic diet (of 5% carbohydrate) “was not associated with significant loss of fat mass” compared to a non-specialized diet with the same calories; there was no useful “metabolic advantage”. In 2017 Kevin Hall, a NIH researcher hired to assist with the project, wrote that the carbohydrate-insulin hypothesis had been falsified by experiment. Hall wrote “the rise in obesity prevalence may be primarily due to increased consumption of refined carbohydrates, but the mechanisms are likely to be quite different from those proposed by the carbohydrate–insulin model”.

Planning
If you need to be on a low-carb diet, make sure to know what you should, and should not, eat. Major no-go food and drink items on a low-carb diet include almost anything made from grain, potatoes and other starchy root vegetables, many varieties of fruit, almost all juices and sugary sodas, as well as most alcoholic beverages. Some low-carb diets emphasize high-fiber foods, such as spinach and broccoli.

If you are flying, check with the airline about a special meal. A few airlines offer low-carb meals; most offer “diabetic” meals. The diabetic meals tend to be lower in refined carbohydrates and lower in fat. Although it may not be exactly what you would choose, it may be a better fit for your diet than the plate of reheated pasta that everyone else will be offered.

If you’ve been following a low-carb diet for a while, then you probably know what fits in your food plan at home. Before you leave, look up foods that you might encounter on the trip, and figure out what works for you. For details about particular foods, check any of the reliable websites you can find in a web search for terms like “low-carb diet”, “keto diet” and “diabetic diet”, and remember that wherever you have Internet access, you can do a search on “[name of item] sugar content”. (For example, on ketogenic diets, it’s often recommended to have no more than 30 grams of non-fiber carbohydrates per day, so you can keep that goal in mind while considering the sugar content of items you’re considering eating.) However, if you will be travelling somewhere with spotty Internet service or worse, it may be important for you to print out lists of sugar quantities for any food you believe you might encounter on the trip.

Health aspects

Adherence
It has been repeatedly found that in the long-term, all diets with the same calorific value perform the same for weight loss, except for the one differentiating factor of how well people can faithfully follow the dietary programme. A study comparing groups taking low-fat, low-carbohydrate and Mediterranean diets found at six months the low-carbohydrate diet still had most people adhering to it, but thereafter the situation reversed: at two years the low-carbohydrate group had the highest incidence of lapses and dropouts. This may be due to the comparatively limited food choice of low-carbohydrate diets.

Body weight
Studies have shown that people losing weight with a low-carbohydrate diet, compared to a low-fat diet, have very slightly more weight loss initially, equivalent to approximately 100kcal/day, but that the advantage diminishes over time and is ultimately insignificant. The Endocrine Society state that “when calorie intake is held constant body-fat accumulation does not appear to be affected by even very pronounced changes in the amount of fat vs carbohydrate in the diet.”

Much of the research into low-carbohydrate dieting has been of poor quality and studies which reported large effects have garnered disproportionate attention in comparison to those which are methodologically sound. Higher quality studies tend to find no meaningful difference in outcome between low-fat and low-carbohydrate dieting. Low-quality meta-analyses have tended to report favourably on the effect of low-carbohydrate diets: a systematic review found that 9 out of 10 meta-analyses with positive conclusions were affected by publication bias.

Cardiovascular health
As of 2016 it was unclear whether low-carbohydrate dieting had any beneficial effect on cardiovascular health, though such diets can cause high LDL cholesterol levels, which carry a risk of atherosclerosis in the long term. Potential favorable changes in triglyceride and HDL cholesterol values should be weighed against potential unfavorable changes in LDL and total cholesterol values.

Some randomized control trials have shown that low-carbohydrate diets, especially very low-carbohydrate diets, perform better than low-fat diets in improving cardiometabolic risk factors in the long term, suggesting that low-carbohydrate diets are a viable option alongside low-fat diets for people at risk of cardiovascular disease.

There is only poor-quality evidence of the effect of different diets on reducing or preventing high blood pressure, but it suggests the low-carbohydrate diet is among the better-performing ones, while the DASH diet performs best.

Diabetes
Overall, the proportion of carbohydrate in a diet is not linked to the risk of onset of Type 2 diabetes, although there is some evidence that a diet containing certain high-carbohydrate items – such as sugar-sweetened drinks or white rice – is associated with an increased risk.

Research into the effectiveness of low-carbohydrate, high fat (LCHF) diets for preventing weight gain and diabetes has produced conflicting results, with some suggestion that diet suitability is not generalizable, but specific to individuals. Overall, for prevention, there is no good evidence that LCHF diets offer a superior diet choice to a more conventional healthy diet, as recommended by many health authorities, in which carbohydrate typically accounts for more than 40% of calories consumed.

There is a lack of evidence of the usefulness of low-carbohydrate dieting for people with type 1 diabetes. Although for certain individuals it may be feasible to follow a low-carbohydrate regime combined with carefully-managed insulin dosing, this is hard to maintain and there are concerns about potential adverse health effects caused by the diet. In general people with type 1 diabetes are advised to follow an individualized eating plan rather than a pre-decided one.

A low-carbohydrate diet gives slightly better control of glucose metabolism than a low-fat diet in type 2 diabetes. A 2018 report on type 2 diabetes by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) found that a low-carbohydrate diet may not be as good as a Mediterranean diet at improving glycemic control, and that although having a healthy body weight is important, “there is no single ratio of carbohydrate, proteins, and fat intake that is optimal for every person with type 2 diabetes”.

The ADA say low-carbohydrate diets can be useful to help people with type 2 diabetes lose weight, but that these diets were poorly defined, difficult to sustain, unsuitable for certain groups of people and that, for diet composition in general, “no single approach has been proven to be consistently superior”. Overall, the ADA recommend people with diabetes should be “developing healthy eating patterns rather than focusing on individual macronutrients, micronutrients, or single foods”. They recommended that the carbohydrate in a diet should come from “vegetables, legumes, fruits, dairy (milk and yogurt), and whole grains”; highly-refined foods and sugary drinks should be avoided.

Low-carbohydrate dieting has no effect on the kidney function of people who have type 2 diabetes.

Historically, limiting carbohydrate consumption was the traditional treatment for diabetes – indeed, it was the only effective treatment before the development of insulin therapy – and when carefully practised, it generally results in improved glucose control, usually without long-term weight loss.

Exercise and fatigue
A low-carbohydrate diet has been found to reduce endurance capacity for intense exercise efforts, and depleted muscle glycogen following such efforts is only slowly replenished if a low-carbohydrate diet is taken. Inadequate carbohydrate intake during athletic training causes metabolic acidosis, which may be responsible for the impaired performance which has been observed.

Ketosis
The ketogenic diet is used to treat drug-resistant childhood epilepsy. It has become a fad diet for people attempting to lose weight. Dieters trying this often do not achieve true ketosis as this requires extreme carbohydrate restriction, and maintaining a ketogenic diet is difficult. Some diet advocates make misleading claims that the ketogenic diet can treat or prevent cancer.

The British Dietetic Association note that a medical ketogenic diet is a useful epilepsy treatment, but for weight loss named it one of the “top 5 worst celeb diets to avoid in 2018”. Celebrities endorsing the diet include Gwyneth Paltrow and Mick Jagger.

High-quality research shows no long-term weight loss advantage to a ketogenic diet over a low fat diet. There is a lack of data about long-term safety.

Safety
Low-carbohydrate dieting is associated with increased mortality, just as high-carbohydrate dieting is.

As of 2018 research has paid insufficient attention to the potential adverse effects of carbohydrate restricted dieting, particularly for micronutrient sufficiency, bone health and cancer risk. One meta-analysis reported that adverse effects could include “constipation, headache, halitosis, muscle cramp and general weakness”.

Ketosis induced by a low-carbohydrate has led to reported cases of ketoacidosis, a life-threatening condition. This has led to the suggestion that ketoacidosis should be considered a potential hazard of low-carbohydrate dieting.

In a comprehensive systematic review of 2018, Churuangsuk and colleagues reported that other case reports give rise to concerns of other potential risks of low-carbohydrate dieting including hyperosmolar coma, Wernicke’s encephalopathy, optic neuropathy from thiamine deficiency, acute coronary syndrome and anxiety disorder.

Significantly restricting the proportion of carbohydrate in diet risks causing malnutrition, and can make it difficult to get enough dietary fiber to stay healthy.

As of 2014 it appeared that with respect to the risk of death for people with cardiovascular disease, the kind of carbohydrates consumed are important; diets relatively higher in fiber and whole grains lead to reduced risk of death from cardiovascular disease compared to diets high in refined-grains.

Challenges and pleasures
One challenge for low-carb dieters who are travelling is the ubiquity and cultural centrality of high-carb foods like bread, rice and noodles. It’s a truism to break bread, or in many languages, to eat rice, so it can be socially difficult to abstain. If you explain that it’s on doctor’s orders for health, more people will understand. Another approach is to have very small quantities of these high-carb foods. Having a scrap of bread to taste is unlikely to hurt a person on a low-carb diet, though be careful how much of it you eat.

But what should you do if you are a guest at someone’s house, and they made only high-carb foods for the meal? If your condition is so acute that eating these foods is likely to make you sick, that’s one thing, but for people who are merely trying to lose weight, a single high-carb meal may not hurt you much, and if it will help you socially, it may be worth it, especially when there is no alternative at that time.

On the other hand, for many low-carb dieters, while indulging in great desserts and bread may be off-limits, unless you are a vegan, you have license to try all manner of cheeses, and if you are not a vegetarian, you can try all kinds of meat as long as there is no problem with flour, breadcrumbs or corn starch in the sauce or sugar in the cure or marinade. There are also various fruits that you may find unproblematic to eat, though you may have to limit quantities. For example, one medium-sized peach contains about 13 grams of sugar, so if you are otherwise on a relatively strict keto diet, eating a single peach is unlikely to push you out of ketosis. Berries are generally relatively low-carb, even when they’re sweet, so adding blueberries or strawberries to your full-fat yogurt can be a healthful indulgence for a low-carb dieter. But surprisingly, even beets are OK in small quantities, as 1 cup of red beets yields only about 9 grams of sugar, so a few pieces of beet in your salad are unlikely to be a problem. In some low-carb diets, small amounts of alcoholic drinks other than beer or mixed cocktails (because those almost always have a sweet component) are also relatively acceptable, though there are different opinions about this.

Restaurant dining
There are challenges and joys of restaurant dining on a low-carb diet. The pasta and dessert courses are generally not for you, but many restaurants are happy to serve you grilled or broiled fish, steak, lamb, or roast chicken. If the side is a problem (potatoes are common), they are often happy to substitute salad or some vegetable, though be prepared to pay a supplement in some cases.

Also, for breakfast or lunch, you often have the option of ordering eggs. For example, an omelet with cheese, possibly a kind of meat and green vegetables such as spinach is very healthy for a low-carb dieter, as long as you avoid having sides made from high-carb sources like potatoes or bread.

Here are some ideas for strategizing meals in restaurants of different types:

Mexican
Cal/Mex and Tex/Mex taquerias work very well with low-carb diets. If you avoid eating the tortilla, you are usually fine eating the rest of the taco. Crunchy corn taco shells have fewer carbs than flour tortillas. Avoid ordering items like burritos that have rice in them, or ask them to leave out the rice. Besides, those are huge, and even on a diet that’s primarily about avoiding too many carbs, portion control is relevant, so consider sharing your meal with your travel partner if you’re traveling with one, rather than ordering your own separate full-sized meals. You’ll save money that way, too.

Italian or Greek
Order grilled items, or in Tuscan restaurants, bistecca alla fiorentina. Start your meal with an antipasto plate of olives, marinated vegetables, sausage or other cured meats if you like, or a salad. If you are in Italy during the summer, get the insalata caprese (a salad of tomatoes, cheese, and basil). Order sides such as green vegetables (for example, leafy ones like spinach and broccoli rabe, zucchini or string beans).

If you are able to order berries with unsweetened cream for dessert, consider doing so. If a possible dessert is Greek yogurt with nuts and honey, ask if they could make it without honey.

Chinese
Get sauteed vegetables and ask for them to be made without corn starch. Have steamed fish with ginger and scallion or unbreaded fried or roasted chicken with garlic. Watch out for sugar in roast or soy sauce meats, as that is traditional in parts of China such as Guangdong province. Chinese food can be difficult for low-carb dieters, as so many sauces have corn starch and/or some sugar in them, and of course rice is traditional, but it is possible to eat Chinese food without rice: At banquets, it’s common to abstain from rice or have some in the form of fried rice at the end only. If you find yourself in a restaurant that specializes in dumplings, pickled vegetables may also be on the menu (this combination is not uncommon in Beijing, for example), and many Cantonese-style dim sum restaurants also will serve larger dishes such as roast chicken or sauteed or steamed vegetables if you order them. Chicken feet and garlic fried shrimp are traditional Cantonese dim sum items that are mainly protein, but see if you can find out whether corn starch is used or can be kept out of the preparation, and spare ribs with black beans may have sugar.

Thai
Thai food can be quite challenging for low-carb dieters, as sugar is one of the traditional tastes. If you have more control over the balance between the different flavors, you may be able to avoid too much sugar. However, be aware that powdered rice is also used, for example, in larb.

North Indian
Tandoori dishes are likely to be low-carb. Otherwise, dry curries are probably less likely to have carby thickeners than curries with more liquid, though ask about flour, corn starch or sugar if you can. If you order lassi, request salty, and if you order masala chai, request no sugar. Potatoes are a common food you will want to avoid. Different kinds of dal (pulses/lentils) have different amounts of carbs, so if you’d like to have more than a little bit of dal, check on the nutritional data for kinds that are on offer.

Middle Eastern
Shawarma is often a good choice, as are kebabs whenever they are made from pieces of meat and not ground meat with flour as a binder. If you order a combination platter, avoid tabouleh, as it’s based on bulgur wheat. Also avoid mujadra, which includes wheat. Falafel is relatively high in sugar, so best eaten in modest quantities, but hummus is very low in sugar.

Turkish
Get kebabs, grilled fish or similar dishes if you are not a vegetarian. There is also excellent sausage, such as sujuk. Excellent salads will serve you well, and there are also mezes you can enjoy. Be careful about stuffed vegetables (grape leaves, peppers, eggplant, etc.), as the filling generally includes rice.

German/Austrian
While you sadly will have to avoid indulging your way through loaves of fantastic German bread or Austrian strudels, there is döner kebab available in most every town. Döner stands often offer a salad form, or you can get a wrap and just not eat the flatbread. You can also dine on wurst to your heart’s content, as long as you skip the potato side dishes and sauces with sugar. And in these lands of fine beers, there are also excellent wines (look for the drier ones on this diet) and Obstler (hard liquors). Some Obstler are sweet liqueurs, but wonderful eaux de vie such as poire williams are also available.

If you are trying to get through the land of beer and pretzels on a budget, then the grocery stores and some bakeries sell Bunte Eier (“colored eggs”), which are hard-boiled eggs. Vegetables in the supermarkets can be surprisingly inexpensive, and mild-flavored cheeses, such as Butterkäse (“butter cheese”), are easy to find. Also, look for very high-fat plain yogurt in Turkish grocery stores: yogurts with 12% milk fat or more are common, deliciously similar in taste to high-quality creme fraiche, and very good for many low-carb diets.